The US is seeking answers on whether Pakistan violated arms sale agreements by using jets built in the States to shoot down an Indian plane.
Pakistan has admitted to gunning down a jet from the neighbouring country after it crossed the Line of Control in disputed Kashmir, as tensions ramped up between the two countries.
However, it has denied using US-built F-16s and having done so could breach the terms they were sold under.
"We are aware of these reports and are seeking more information," a US Embassy spokesperson told Reuters.
"We take all allegations of misuse of defence articles very seriously."
The United States often inserts restrictions on how its exported military hardware can be used.
These are detailed through so-called end-user agreements.
At least eight civilians and two soldiers have been killed in Kashmir since tensions soared following India's airstrike on Pakistan last Tuesday.
India said this targeted militants behind a February 14 suicide bombing in Indian-controlled Kashmir that killed 40 Indian troops.
Pakistan retaliated by shooting down the fighter jet on Wednesday and detaining its pilot.
However, he was returned to India on Friday.
India then handed over the body of a Pakistani civilian prisoner beaten to death by inmates in a jail in India last week.
The man, Skahir Ullah, was buried later on Sunday in his home village of Sialkot in Punjab province.
Residents near the disputed boundary in divided Kashmir region said on Sunday it had been quiet overnight following days of back and forth between opposition fighters.
Kashmir has been divided between India and Pakistan practically since their independence from British rule in 1947 and the two countries each claim Kashmir in its entirety.
They have fought two of the three wars between them over it.
Though the rivals struck a cease-fire deal in 2003 they regularly violate it and trade cross-border fire.
