From The Washington Post:
The Pentagon is unable to account for more than $500Â million in U.S. military aid given to Yemen, amid fears that the weaponry, aircraft and equipment is at risk of being seized by Iranian-backed rebels or al-Qaeda, according to U.S. officials.
With Yemen in turmoil and its government splintering, the Defense Department has lost its ability to monitor the whereabouts of small arms, ammunition, night-vision goggles, patrol boats, vehicles and other supplies donated by the United States. The situation has grown worse since the United States closed its embassy in Sanaa, the capital, last month and withdrew many of its military advisers.