The nation’s efforts to screen refugees, asylum seekers and visitors are broken and expose the nation to potential terrorist attacks, says a report from The Investigative Project on Terrorism.

The IPT report — titled “America’s Refugee, Asylum, and Visa Waiver Programs: Our Entire Access System is Broken” — highlights current weaknesses in the system that terrorists have manipulated to gain access to the U.S.

Terrorists have already used the Visa Waiver Program — which allows the nationals of largely European countries to travel to the U.S. for short term travel without a visa — to gain access to the U.S., the report says.

For example, according to IPT, 9/11 conspirator Zacarias Moussaoui and “shoe bomber” Richard Reid both used the Visa Waiver program to fly to the U.S.

“The European Union (EU) Terrorism Situation and Trend Report of 2007 stated that several Islamic terrorist suspects were arrested in VWP countries in 2006: one was arrested in Belgium; nine in Denmark; 139 in France; 11 in Germany; 34 in Italy; 51 in Spain; three in Slovakia; and three in Sweden,” the report reads.

Stolen passports from VWP countries represent another area of weakness, according to the report. Terrorists have been found with altered passports.

Terrorists’ use of manipulated VWP passports is most disturbingly demonstrated by the entry of Ahmed Ajaj to the U.S. using a photo-substituted Swedish passport on September 1, 1992. Ajaj was sent to secondary inspection by the Immigration and Naturalization Service (INS) after arriving at New York’s JFK International Airport on a flight from Peshawar, Pakistan. Inspectors found six bomb-making manuals, notes that Ajaj had taken during explosives courses, videotapes calling for terrorist attacks against the U.S., and multiple fake passports and identification documents. Ajaj was arrested for passport fraud and illegal entry and spent six months in jail.

From his cell, Ajaj took part in the planning of the first bombing of the World Trade Center, which occurred on February 26, 1993.

After the bombing, the investigation revealed that from jail Ajaj had over 20 Arabic conversations with Ramzi Yousef and other individuals involved in the World Trade Center bombing. Yousef, the nephew of 9/11 mastermind Khalid Sheik Mohammed, traveled to the U.S. on the same flight as Ajaj. Yousef boarded the flight with a fake British passport, yet presented an Iraqi passport and requested asylum upon entry to the U.S.

Another area of vulnerability the report says is the refugee and asylum processes in the U.S.

The Obama administration is planning to admit at least 10,000 Syrian refugees to the U.S. this fiscal year. The report notes that the dramatic increase in refugee admissions from Syria represents a 277-fold increase over the 2013 level when 36 Syrian refugees were admitted.

Additionally, America’s northern neighbor, Canada, has also moved to accept 25,000 refugees in 2016, “some of these will no doubt make their way south over a border that is not difficult to traverse.The Canadian government’s stated preference for refugee women and children will not prevent terrorists from attempting to gain entry among the refugees.” the report argues.

According to IPT, terrorist abuse and manipulation of the immigration system in the U.S is not new. It points to the 9/11 Commission Staff Report on Terrorist Travel which read:

Terrorists in the 1990s, as well as the September 11 hijackers, needed to find a way to stay in or embed themselves in the United States if their operational plans were to come to fruition….[T]his could be accomplished legally by marrying an American citizen, achieving temporary worker status, or applying for asylum after entering. In many cases, the act of filing for an immigration benefit sufficed to permit the alien to remain in the country until the petition was adjudicated. Terrorists were free to conduct surveillance, coordinate operations, obtain and receive funding, go to school and learn English, make contacts in the United States, acquire necessary materials, and execute an attack.

Some of the terrorists who manipulated the system in this fashion were the 1993 World Trade Center bombers including the blind sheikh Omar Abdel Rahman. Others were able to stay in the country by marrying U.S. citizens including Siddig Ibrahim Siddig Ali, Mohammed Saleh, El Sayyid Nosair, Amir Abdelgani, Fadil Abdelgani, Tarig Elhassan, Matarawy Mohammed Said Saleh.

Other national security risks, according to the report, were able to gain access to the U.S. via the refugee and asylum route. These failures include the admission of:

-Pakistani asylum seeker Mir Amal Kansi, who killed two people outside CIA Headquarters in January 1993.

-Wadi El Hage, who was involved in the 1998 Africa Embassy bombings and was the personal secretary of Osama bin Laden. He worked at Al Kifah refugee center in New York…. [which] has been described as “al-Qaeda’s recruitment center in the US”

-Fawaz Damrah, who was an imam at the Islamic Center of Cleveland and a chief fundraiser for Palestinian Islamic Jihad. He was charged with criminal naturalization fraud; among his false statements was his concealment of the activities of Al Kifah Refugee Center in New York.

Additionally, the report points to the two Iraqi refugees arrested in Bowling Green, Kentucky in 2009 who had provided support to terrorists in Iraq and who planned to attack U.S. troops in the United States.

The report also pointed to Sen. Jeff Sessions’ list of 12 refugees who passed the screening process but were caught in 2015 plotting terrorist attacks.

The Boston Marathon bombers Tamerlan and Dzhokhar Tsarnaev also make an appearance in the report as examples of flaws in the asylum process.

“Boston Marathon bombers Tamerlan and Dzhokhar Tsarnaev came to the United States as children and received asylum through their parents,” the report reads. “A set of Albanian brothers of Macedonian origin involved in the foiled plot against soldiers at Fort Dix in New Jersey were from a refugee family who came to the U.S. illegally as minor children with their parents. Their father reportedly sought asylum in 1984 but his asylum application was ignored for two decades.”

According to IPT, the VWP, the refugee and asylum processes have been inadequate for years, however the situation has deteriorated under President Obama. At the core, the report argues, is the United Nations High Commissioner for Refugees (UNHCR) policy of trusting refugees at their word, granting them “the benefit of the doubt.”

The UNHCR’s Handbook And Guidelines On Procedures And Criteria For Determining Refugee Status instructs U.N. interviewers to give refugees “the benefit of the doubt.” If the U.N. gives a refugee “the benefit of the doubt” and doesn’t articulate its suspicions, concerns, or issues, this could present a vulnerability during the refugee’s next interview with U.S. officials. It would be beneficial for the U.S. government to request that the U.N. require its workers to specifically articulate any doubts, issues, or concerns that they may have had during the course of an interview – especially if the refugee is ultimately referred to and processed by Citizenship and Immigration Services (CIS) with a “benefit of the doubt.”

Another concern the report highlights as a weakness in need of reform is the quickness with which refugees are able to adjust their status to lawful permanent residency — within a year.

“This is entirely too rapid a process,” the report reads. “A lot can change in a single year that could materially affect one’s asylum status, including the conditions in the country from which the asylee or refugee came. Furthermore, a refugee who flees Syria, enters the U.S. and obtains a green card one year after entering has barely had enough time to become familiar with U.S. laws.”

While refugees are not allowed to return to the country from where they fled, once they obtain permanent residency they are free to travel to that country, according to the report.

“In theory, a Syrian could enter the U.S. as a refugee, obtain green card status, and return to Syria in as quickly as 366 days. Obviously, this development presents problems,” the report reads.

IPT makes a number of recommendations to improve the system including more coordination among agencies and countries, increased fraud investigations and continued vetting post-entry. As well as improvements to the refugee and Electronic System for Travel Authorization — which determines if a traveler may participation in the VWP — applications.

The legislative fixes suggested by the report include:

-Extend the time period in which refugees are able to obtain permanent residency from one year to three years (or more). The same extension should be provided for individuals granted asylum in America. This proposed legislative change would require that 8 CFR 209 be amended.

-Extend the statute of limitations for charges of lying on ESTA, refugee, and asylum applications from five years to 10. There is already a 10-year precedent for similar immigration related crimes including passport and naturalization fraud.

-Eliminate the “benefit of the doubt” standard and ask the U.N. to explain to Congress its process for granting it so that an informed decision can be made about refugee vetting. Congress should explicitly forbid U.S. officials from employing it.

-Pressure the U.N. to make its fingerprint database available, or be forthcoming with fingerprint hits in which a refugee used a different name(s) and/or date(s) of birth or applied/registered with UNHCR in multiple refugee camps in multiple countries.

– VWP countries should be asked to share their criminal history and fingerprint databases so that the United States can better vet applicants’ backgrounds. Congress should appropriate funding to ensure at least two ICE and CBP personnel are stationed in each of the Visa Waiver countries. Absent that, those countries should appoint officials in their U.S. embassies to serve as VWP points of contact for DHS.

– VWP countries that fail to report passport thefts or fail to share biometrics and criminal history of their citizens should immediately be suspended from the program.

-Congress should consider appropriating more money to help speed up the system. That includes more immigration judges, more ICE-HIS agents to investigate immigration fraud, and more lawyers for the Office of the Principal Legal Adviser (OPLA) to litigate removal proceedings. EOIR’s two-year backlog49 can only be brought up to speed with additional resources, which are badly needed for the increasing immigration volumes. An alien in limbo in removal proceedings with EOIR is just as much of a security concern as an alien seeking an immigration benefit with CIS. Both should be given adequate resources and backlogs endanger national security just as much as lax vetting.

The full report is available here.