The United States is “seeking information” on whether Pakistan used U.S.-built F-16 jets to down an Indian warplane, the U.S. Embassy in Islamabad said on Sunday, which may violate the F-16 sale agreements between Washington and Pakistan.

Pakistan says it did not use F-16s in shooting down an Indian warplane when it crossed the Line of Control that acts as a de facto border in Kashmir. Islamabad says this was an act of self defense.

“We are aware of these reports and are seeking more information,” a U.S. Embassy spokesperson told Reuters. “We take all allegations of misuse of defense articles very seriously.”

U.S. often inserts restrictions on how its exported military hardware can be used through so-called end-user agreements. (NAN)