Turkey has signed a deal for its first major weapons purchase from Moscow to buy S-400 missile defence systems, both sides announced Tuesday, in an accord that could trouble Ankara's NATO allies.
The purchase of the surface-to-air missile defence batteries, Ankara's most significant deal with a non-NATO supplier, comes with Turkey in the throes of a crisis in relations with several Western states.
"Signatures have been made for the purchase of S-400s from Russia. A deposit has also been paid as far as I know," Turkish President Recep Tayyip Erdogan said in comments published in several newspapers on Tuesday.
"Mr Putin (President Vladimir Putin) and myself are determined on this issue," he told Turkish journalists aboard his presidential jet returning from a trip to Kazakhstan.
Moscow also confirmed the accord, with Vladimir Kozhin, Putin's adviser for military and technical cooperation, saying: "The contract has been signed and is being prepared for implementation."
- 'Take our own decisions'-
The purchase of the missile systems from a non-NATO supplier is raising concerns in the West over their technical compatibility with the alliance's equipment.
The Pentagon has already sounded the alarm, saying bluntly that "generally it's a good idea" for NATO allies to buy inter-operable equipment.
A NATO official told AFP that interoperability was "fundamental" to the alliance for the conduct of joint missions.
"No NATO ally currently operates the S-400," the official noted, adding that: "NATO has not been informed about the details of any purchase."
But Erdogan said Turkey -- which has the second largest standing army in NATO after the United States -- was free to make military acquisitions based on its defence needs.
"We make the decisions about our own independence ourselves, we are obliged to take safety and security measures in order to defend our country," he said.
He said Moscow would also extend a credit to Turkey for the purchase of the weapons. No financial details have been disclosed.
- 'Signal resentment to West' -
However, signing the deal does not mean that delivery is imminent, with Russia facing a high demand for the S-400s from its own armed forces and key clients like China and India.
Some analysts have suggested the message sent to the West by the military cooperation between Moscow and Ankara is as important as the delivery itself.
In 2015, Turkey scrapped a $3.4- billion (2.8-billion-euro) deal with China to build its first anti-missile system.
Aykan Erdemir, senior fellow at the Foundation for Defense of Democracies, said the accord will hasten Ankara's "drift from the transatlantic alliance and values".
The purchase "is more about signalling resentment against the West than serving Turkey's pressing security needs," he told AFP.
Ozturk Yilmaz, deputy leader of the opposition CHP party, said the party was not opposed to the buy but argued such weapons should be produced in Turkey to lessen the country's dependence on outside suppliers.
Both Ankara and Moscow have an interest in signalling to the West they mean business with the military cooperation.
Russia's relations with NATO have been in crisis over its annexation of Crimea from Ukraine and for backing pro-Moscow separatists in eastern Ukraine.
Turkey, a NATO member since 1952, has currently troubled ties with the United States over a number of issues including Washington's support for the People's Protection Units (YPG) Syrian Kurd militia which Ankara considers a terror group.
The Turkish-Russian contract is a symbol of better relations between Ankara and Moscow after a reconciliation deal was signed last year following the 2015 shooting down by the Turkish military of a Russian plane over the Syrian border.
But the two nations -- whose rivalry in the Black Sea and Caucasus regions dates back centuries -- are still at odds on a host of political issues.
Turkey, which vehemently opposed the 2014 annexation of Crimea, strongly condemned Tuesday the jailing of a Tatar leader for eight years by Russia over a rally against Moscow's seizure of the region.
Akhtem Chiygoz, a former deputy head of the Tatars' traditional decision-making assembly, was arrested in 2015 over clashes at a rally that left two people dead.