"We are proud that the most advanced F-16 ever produced will help protect Peru's national sovereignty while strengthening the enduring partnership between our nations," Lockheed Martin's vice president said in a statement.

Peru's foreign and defense ministers quit on Wednesday after the country's interim president announced he was putting the deal on hold until after presidential elections in June.

The two ministers said the decision by interim president Jose Maria Balcazar undermined Peru's reputation, insisting that the contracts with Lockheed Martin had already been signed.

The total value of the deal has not been made public.

Peru's economy minister said Wednesday evening he had made a first payment of $462 million to Lockheed Martin.

The US ambassador to Peru, Bernardo Navarro, told Radio Exitosa that Lima had purchased a first squadron of 12 jets, due for delivery from 2029, and that "another 12 will arrive later."

- 'Milestone' deal -

In a statement on X, he confirmed that a "technical signing" of the deal took place on Monday, "with the full knowledge of the highest level of the Peruvian government" after an earlier signing ceremony was called off at the last minute.

"Today marks a milestone in our 200-year history" of US-Peruvian relations, Navarro said.

In October 2024, Peru said that it would renew its ageing air defense fleet with the purchase of 24 state-of-the-art fighter jets for an estimated $3.5 billion.

The South American country currently has 12 Mirage 2000 aircraft, according to defense publications, as well as Russian MiG-29s and Belarusian Sukhoi Su-27s, most of which are inoperative or in reserve.

Balcazar said he halted the defense deal to ensure that public funds were "used appropriately."

The deal became swept up in a presidential election marred by logistical problems, unsubstantiated fraud allegations and delays to the ballot count.

Eleven days after Peruvians voted in the first round, it is still not known who will face off against conservative frontrunner Keiko Fujimori in June's runoff.

Ultraconservative former Lima mayor Rafael Lopez Aliaga is locked a tight race with leftist ex-minister Roberto Sanchez for the second runoff spot.