The Pentagon stopped a weapons delivery to Ukraine during its conflict with Russia, pointing to low stockpiles of specific munitions in the Defense Department arsenal. The halted delivery included critical air defense missiles that Ukraine has lobbied the United States for to protect against Russian aerial warfare.

The move "was made to put America’s interests first," a White House spokeswoman said, as U.S. munitions have been depleted in recent years.

The Pentagon review determined that stocks were too low on some items previously pledged, so pending shipments of some items won’t be sent, according to a U.S. official, who spoke on condition of anonymity to provide information that has not yet been made public.