More than two months after they were promised, U.S. weapons and ammunition have not reached America’s allies among the Syrian rebels, and their delivery date remains unclear, according to the Syrian opposition and Middle Eastern diplomats.

Khalid Saleh, an official of the Syrian Opposition Coalition, said in a telephone interview from Turkey that, while U.S. officials continue to promise arms, “nothing has come through yet, and we haven’t been given a specific date when we’ll see them.” The rebels, who have been pressing for months for anti-tank and antiaircraft weapons, have still not been told what kind of military aid they will receive, he said…

The deliveries, which White House officials promised in “weeks, not months,” were seen as a step toward greater U.S. military involvement. U.S. agencies have so far provided only nonlethal equipment, such as mobile radios, and $1 billion in humanitarian aid.

But, as the slow pace of the arms deliveries underscores, the administration remains conflicted about the move. Fearing that the arms could fall into the hands of Islamist militants who make up a growing part of the rebel forces, officials have been moving carefully to vet potential recipients of the arms.