India has lodged a protest with the US for finalising a deal to provide a $450-million sustenance package for Pakistan’s F-16 fleet.

On September 14, Indian Defence Minister Rajnath Singh talked to US Defence Secretary Lloyd Austin over the phone and conveyed his country's concerns to the US official.

The US-built aircraft are a critical part of the military arsenal of Pakistan, whose arch-rival India worries that the fleet could be used against it by its neighbour.

Taking to Twitter, Singh said, “I conveyed India’s concern at the recent US decision to provide a sustenance package for Pakistan’s F-16 fleet."

“Had a warm and productive telephonic conversation with the US Secretary of Defence, Mr Lloyd Austin. We discussed the growing convergence of strategic interests and enhanced defence & security cooperation.”

“We also discussed ways to strengthen technological and industrial collaboration and also explore cooperation in emerging and critical technologies,” he said.

Last week, Indian officials raised the same concerns while talking to US Assistant Secretary of State Donald Lu.

Austin congratulated Singh on the INS Vikrant's commissioning and emphasised the significance of the occasion for India's position as a provider of security in the Indo-Pacific, according to a readout issued by the US Defence Department.

“In light of the evolving regional security environment, the two defence leaders committed to expanding information-sharing and logistics cooperation as the US and Indian militaries operate and coordinate more closely together,” it stated.

“They reviewed the multi-faceted India-US defence cooperation and reiterated mutual commitment to further strengthen military-to-military ties.”

Pakistan, which like India is nuclear-armed, has relied heavily on Chinese-made jets, but the F-16s remain the most effective and advanced in its fleet.