Russian S-400 anti-missile system
Russian S-400 anti-missile systemReuters

Turkey's Defense Industries Chair Ismail Demir said on Monday that an agreement in principle has been reached with Russia on the supply of the second batch of Russian made S-400 air defense system.

"We have a principle agreement on the supply of the second system. We are talking about technical details. There is no question mark about supply," said Demir, according to the Xinhua news agency.

The second phase of the purchase includes certain joint production and technology transfers, based on the agreement, he added.

Turkey signed a contract with Russia in 2017 to purchase the S-400 system, raising the ire of the United States.

The first parts of the S-400 air defense system were delivered to Turkey in July of 2019. Russia then delivered a second battery of S-400s a month later.

US has threatened Turkey with sanctions, but said it would be spared from these measures under a 2017 law if the S-400 system is not turned on.

Turkey, for its part, has made clear it will use the Russian system despite US threats of sanctions.