WASHINGTON: The US reprimanded Pakistan Air Force chief in August for misusing F-16 fighter jets by undermining their shared security platforms and infrastructures, a media report here has said, months after the Indian Air Force shot down an F-16 jet of Pakistan Air Force during an aerial combat over Kashmir.

Andrea Thompson, the then-undersecretary of State for Arms Control and International Security Affairs, wrote a letter to Pakistani Air Force Chief Air Chief Marshal Mujahid Anwar Khan in August over the matter, US News reported on Wednesday.

While the letter written did not directly mention the incidents in the immediate aftermath of the February 26 Balakot airstrikes, US News quoted a source as saying that the communication served as a direct response to America's concerns about the F-16 use over Kashmir in February.

"While we understand from you that these aircraft movements were done in support of national defense objectives, the US government considers the relocation of aircraft to non-US government authorised bases concerning and inconsistent with the F-16 Letter of Offer and Acceptance," Thompson said in his letter.

A suicide bomber of Pakistan-based Jaish-e-Mohammed (JeM) terror group killed 40 CRPF personnel in Jammu and Kashmir's Pulwama district on February 14.

India launched a counter-terror operation against a JeM training camp in Balakot on February 26. The next day, Pakistan Air Force retaliated and downed a MiG-21 in an aerial combat and captured its pilot Wing Commander Abhinanadan Varthaman, who was later released.

The IAF had said that during the aerial engagement on February 27, one of its MiG-21 Bison shot down a F-16.

The Indian Air Force on February 28 displayed pieces of the AMRAAM missile, fired by a Pakistani F-16, as evidence to "conclusively" prove that Pakistan deployed US-manufactured F-16 fighter jets during an aerial raid targeting Indian military installations in Kashmir.

"Such actions could subject sensitive US-technologies to diversion to or access by third parties and could undermine our shared security platforms and infrastructures," warned Thompson, who has now left the government.

The State Department and the Embassy of Pakistan has refused to comment on the letter.

According to US News, in her letter, Thompson raised concerns about American access to the bases and the US-made equipment there.

Thompson said it had been four years since Office of Defence Representative of Pakistan – the office that carries out defence cooperation with partner countries – had been allowed to perform an assessment of the security vulnerabilities on the Pakistani bases, the news report said.