The U.S. State Department, when requesting American taxpayer funds to finance assistance for Afghan refugees in Iran, relies on unverifiable data that a United Nations agency obtains from the Islamic Republic, according to a watchdog agency appointed by Congress.

A recent news report revealed that Iran is exploiting Afghan refugees by coercing them to fight alongside forces loyal to Syrian dictator Bashar al-Assad, often leading them to their death.

“As a result of more than three decades of war and instability, millions of Afghans have fled to Pakistan, Iran, and other neighboring countries,” reports the congressionally appointed Special Inspector General for Afghanistan Reconstruction (SIGAR) in an audit released Thursday.

“Since 2002, the Department of State (State) has allocated more than $950 million in Migration and Refugee Assistance funds to assist Afghan refugees living in Pakistan and Iran, facilitate voluntary repatriations to Afghanistan, and help returnees and internally displaced persons,” it adds.

Since it did not have access to Iran, SIGAR was unable to specifically say how much of the $950 million in Afghan refugee assistance has gone to the estimated 950,000 believed to be living in Iran.

State’s refugee and returnees programs are overseen by the department’s Bureau of Population, Refugees, and Migration (PRM).

Through that bureau, the U.S. provides funding primarily to the United Nations High Commissioner for Refugees (UNHCR), but also to the International Organization for Migration (IOM), and other international and non-governmental organizations to assist Afghan refugees residing in Pakistan and Iran, as well as returnees to Afghanistan.

UNHCR relies on “the Pakistani and Iranian governments’ refugee registration systems to identify the number of Afghan refugees residing in those countries and use this information, along with other factors, to help justify their funding decisions to assist those refugees,” notes SIGAR.

In turn, State relies on the data that UNCHR obtains from the Iranian and Pakistani government “to help inform its annual funding requests to Congress for programs intended to support Afghan refugees,” adds the watchdog agency.

While the UN refugee agency has access to Pakistan’s process for registering Afghan refugees living there, it has no involvement in the Iranian processes, relying exclusive on the Islamic Republic’s own reports, notes SIGAR.

State PRM officials told SIGAR that “the accuracy of the data on the number of refugees plays a substantial role in the development of UNHCR’s funding requirements and therefore can impact the level of annual contributions that [the U.S.] provides to UNHCR for Afghan refugees living in Pakistan and Iran.”

However, State is unable to verify the accuracy of the UNHCR data related to Afghan refugees in Iran and has a limited ability to independently verify the information of the refugees living in Pakistan, notes the watchdog.

The U.S. also has a limited ability to monitor the American taxpayer-funded refugee programs in Iran.

“State PRM officials stated that in the absence of U.S. government relations with or presence in Iran, the bureau has limited options to monitor its programs in that country and is unable to verify the accuracy of reporting on the refugee situation,” reports SIGAR. “As a result, State is reliant on UNHCR, other international organizations, and non-governmental organizations for information.”

Agence France-Presse (AFP) reported earlier this week that the government of Iran is exploiting Shiite refugees who have fled Afghanistan by coercing them to fight for Assad in Syria.

Moreover, State’s July 2015 Trafficking in Persons Report mentions that in Iran, “Afghan boys and men are subjected to forced labor and debt bondage in agriculture and construction.”

It is unclear if the exploited Afghans mentioned in the report are refugees.

Corruption and a lack of ministerial capacity have prevented Afghanistan from implementing a long-term refugee strategy.

As a result, “State currently has no plans to provide monetary assistance” to the Afghan Ministry of Refugees and Repatriation.

UNCHR is also having problems with inaccurate Afghan refugee data coming out of Pakistan.

The UN agency “estimates that there are approximately 23,000 deaths among Afghan refugees in Pakistan each year. However, the Pakistani government reported only nine total deaths among Afghan refugees from January 2008 through June 2014.”

According to UNCHR, as of December 2014, “nearly 2.5 million Afghans—1.5 million registered refugees and approximately 1 million undocumented Afghans—were living in Pakistan, and another 950,000 registered Afghan refugees were living in Iran.”