The US has suspend the participation of its ally Turkey in the F-35 stealth fighter jet programme after Ankara decided to buy Russian S-400 air defence system.
Turkey's Foreign Minster Mevlut Cavusoglu met his Russian counterpart Sergei Lavrov last week, giving a go ahead to the S-400 purchase.
The United States has been clear that Turkey's acquisition of the S-400 is unacceptable, said Acting Chief Pentagon Spokesperson Charles Summers Jr.
Should Turkey procure the S-400, their continued participation in the F-35 program is at risk," Summers said.
Regretting the situation facing US-Turkey partnership in the F-35 programme, Summers said the Department of Defense is taking prudent steps to protect the shared investments made in this critical technology and ensure resiliency of the F-35 supply chain.
He said that secondary sources of supply for Turkish-produced parts are now in development.
Our important dialogue on this matter will continue, however, until they forgo delivery of the S-400, the United States has suspended deliveries and activities associated with the stand-up of Turkey's F-35 operational capability, he said.
Turkey-based companies manufacture parts for all F-35 variants and customers. The plane's manufacturer, Lockheed Martin, said that contracts with Turkish companies to build F-35 parts had been expected to reach USD 12 billion, media reports said.
The development gains importance because India too has decided to buy the S-400 system from Russia. The S-400 is known as Russia's most advanced long-range surface-to-air missile defence system.
However, in recent weeks, US officials have said that India and Turkey cannot be compared even if both of them are buying S-400 from Russia.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)