United States military officials admitted to members of Congress that they lost more than $500 million in U.S. military equipment given to Yemen, including guns, ammunition, helicopters, Humvees, night-vision goggles, and patrol boats, The Washington Post reports.

The situation has grown worse since the U.S. closed its embassy in the Yemen capital Sanaa last month, and officials told the Post that they fear the equipment may have fallen into the hands of Iranian-backed rebels or al-Qaida.

The information was disclosed to members of Congress in recent weeks during closed-door meetings with military officials. Pentagon officials said they have no leads on the whereabouts of the missing equipment, and that there is not much they can do to prevent the weapons from falling into the hands of terrorists.

Since 2007, the U.S. has supplied equipment to the Yemeni government through various Defense Department and State Department programs, but when the government was toppled by Shiite Houthi rebels in January, many U.S. forces withdrew and all accountability went out the window.

"We have to assume it's completely compromised and gone," a Capitol Hill legislative aide speaking on the condition of anonymity told the Post.

Another defense official told the paper, "Even in the best-case scenario in an unstable country, we never have 100 percent accountability."

Pentagon officials have taken precautionary measures and diverted about $125 million in military hardware to other countries in the Middle East and Africa.

According to the Post, the following is a list of equipment presumed to be missing:

  • 1,250,000 rounds of ammunition
  • 200 Glock 9 mm pistols
  • 200 M-4 rifles
  • 4 Huey II helicopters
  • 2 Cessna 208 transport and surveillance aircraft
  • 2 coastal patrol boats
  • 1 CN-235 transport and surveillance aircraft
  • 4 hand-launched Raven drones
  • 160 Humvees250 suits of body armor
  • 300 sets of night-vision goggles

The mishap stems from the U.S.'s policies of combating terrorism by training and equipping foreign militaries to fight insurgencies. In every country the U.S. militarily intervenes, it seems as though millions of dollars in weapons either disappear or end up in the hands of terrorists.

Following the U.S.-led Iraqi invasion in 2003, the U.S. spent $25 billion to train and arm Iraqi security forces. The Pentagon admitted in 2007 that it lost track of about 190,000 Ak-47 assault rifles and pistols given to those Iraqi forces between 2004 and 2005, reported The Washington Post. Many of those Iraqi forces were eventually defeated by the Islamic State group in 2014, who confiscated U.S.-supplied weapons, notes RT.

In 2014, The Washington Times reported that the Pentagon admitted to losing track of 40 percent of the firearms it provided to Afghanistan's security forces.

In Syria, the U.S. has been arming "moderate" rebel groups to fight against both Syrian President Bashar al-Assad and the Islamic State group. However, a number of reports have emerged indicating that a large number of these so-called moderate groups, including the Free Syrian Army, have disbanded, with members defecting, along with their U.S.-supplied weapons, to terrorist groups such as the Nusra Front or even the Islamic State.

"The moderate movement in Syria could be considered official dead as of last week, when the last U.S.-backed rebel faction, Harakat Hazzm, disbanded, its members joining extremist groups such as the Nusra Front, the al Qaeda offshoot in the country," the International Business Times reported last week.

"There is no such thing as the Free Syrian Army," Rami Jarrah, a Syrian activist and co-founder of Syrian news outlet ANA Press, told IBT. "People still use the term in Syria to make it seem like the rebels have some sort of structure. But there really isn't."