American troops in Afghanistan have suffered a second insider attack in just days as an Afghan counterpart wounded seven U.S. troops over the weekend. The Taliban again claimed to have infiltrated the U.S. taxpayer-funded Afghan National Defense and Security Forces (ANDSF).

U.S. and Afghan officials have expressed skepticism towards the Taliban claims.

Nevertheless, Saturday’s attack comes a week after an Afghan soldier turned his weapon on his American allies on June 10, killing three and wounding one.

The most recent incident, officially known as a “green-on-blue” attack, also resulted in the death of one Afghan soldier and injury on another.

ANDSF members have born the brunt of the casualties in recent years, including insider assaults.

The U.S.-NATO mission, known as Resolute Support, acknowledged that an Afghan soldier wounded seven American troops in northern Afghanistan’s Camp Shaheen in Balkh province, adding that they had been “evacuated for treatment.”

Referring to Saturday’s attack, the Long War Journal (LWJ) reports: “The Taliban claimed credit for the attack in a statement released on its website, Voice of Jihad. According to the Taliban, ‘Masood from Paktia province’ was ‘working inside Shaheen Corps’ with the Afghan commandos.”

The statement echoes that one issued after the June 10 attack. This latest “green-on-blue” incident may mark the fourth one this year, according to a U.S. watchdog agency.

As of the end of March, there were two possible attacks in which ANDSF troops, including police and army units, turned their weapons against U.S. troops, reported the Special Inspector General for Afghanistan Reconstruction (SIGAR).

One of the “green-on-blue” assaults resulted in no casualties, but the other wounded three American service members, though not critically. The Pentagon is still investigating the latter.

There have been two incidents since SIGAR shared its insider attack tally for this year.

“From January 1, 2017, through February 24, 2017, there were 12 insider attacks in which ANDSF personnel turned on fellow ANDSF personnel. These attacks killed 12 Afghan personnel and wounded eight,” noted the inspector general.

The latest insider attack occurred at the scene of one of the deadliest assaults against Afghan troops. Ten Taliban fighters, who passed through security checkpoints dressed in Afghan army uniforms, slaughtered more than 140 Afghan soldiers at the Afghan National Army’s 209th Shaheen Corps Headquarters in Balkh province’s Mazar-i-Sharif.

Taliban jihadists also claimed then to have infiltrated the Afghan army.

“In the past, the Taliban has infiltrated Afghan security forces to carry out such strikes or convinced soldiers or policemen to turn their weapons on coalition personnel,” points out LWJ.

President Donald Trump has granted the Pentagon the authority to escalate the war in Afghanistan. The Pentagon is expected to deploy as many as 4,000 additional troops to the country.

In total, at least 2,254 American troops have been killed since the war started in 2001, according to the Pentagon. The majority (1,857) of them lost their lives during combat operations.

At least 20,240 other U.S. troops have been injured in action. Most of the casualties during the ongoing Afghanistan war took place under the former president’s watch.