The United States said it is closely following reports that claim Pakistan used US-supplied F-16 fighter jets in the aerial confrontation with India on February 27.

“We’ve seen those reports and we’re following that issue very closely,” US State Department Deputy Spokesperson Robert Palladino said during a press briefing on Tuesday. He was responding to questions on whether Pakistan has violated the end-user agreement on F-16 that it procured from the US.

India on Tuesday said the deployment of F-16 aircraft by Pakistan Air Force and multiple launches of AMRAAMs or advanced medium range air to air missiles were “conclusively observed” by the Indian military during the February 27 dogfight. It also refuted reports that Pakistan had shot down a Sukhoi-30 aircraft of the Air Force. National Security Advisor Ajit Doval reportedly spoke to his US counterpart John Bolton and reportedly briefed him on India having proof of Pakistan’s use of F-16 fighter jets, reported IANS.

“I can’t confirm anything, but as a matter of policy, we don’t publicly comment on the contents of bilateral agreements that we have in this regard involving US defence technologies nor the communications that we have with other countries about that,” Palladino said. “So, we’re taking a look and we’re going to continue to take a look.”

Pakistan has denied using F-16 jets during the dogfight and has not specified which planes it used. It also denied that one of its planes had been downed by the Indian Air Force.

Palladino reiterated that the US will continue to urge India and Pakistan to take steps to de-escalate the situation. “And we believe strongly that further military activity will exacerbate the situation,” he said. “So we reiterate our call for Pakistan to abide by its United Nations Security Council commitments to deny terrorists sanctuary and to block their access to funds.”

Palladino said Secretary of State Mike Pompeo played an essential role in de-escalating the tensions between the two countries. Pompeo led diplomatic engagement directly and spoke with India’s Minister of External Affairs Swaraj, National Security Advisor Doval, and Pakistan’s Foreign Minister Shah Mahmood Qureshi.