The components of the first S-400 missile system battery of Turkey was delivered at Akıncı Air Base of Turkish Air Force at Ankara onboard an An-124-100 military transport aircraft of Russia Air Force's 224th Flight Unit with RA-82038 register early morning today, according to military analyst Babak Taghvaee.
The Pentagon for months has stressed a looming compatibility issue with Turkey using a Russian-made missile system while flying the F-35, something US officials perceive as a national security threat to the jet program.
Ankara's purchase of the surface-to-air missile defence systems caused tensions in relations with its North Atlantic Treaty Organisation ally, the US.
Cristian Maggio, head of emerging markets strategy at TD Securities, said markets had barely begun to react to the S-400 delivery and that United States sanctions risks should not be underestimated.
NATO, which counts Turkey as one of its members, is "concerned about the potential consequences" of the purchase, an official told AFP. In response, the Pentagon is expected to announce that Turkey will be barred from receiving the new F-35 fighter.
After meeting President Donald Trump at a G20 summit last month, Turkish President Recep Tayyip Erdoğan said the USA did not plan to impose sanctions on Ankara for buying the S-400s.
Turkey also said it would keep the USA and Russian equipment separate to avoid allowing Russian access to US stealth technology.
News about Russian-Turkish talks on the delivery of the S-400 systems first came in November 2016. Turkish broadcasters showed footage of one plane parked at air base and a second one landing at around 12.30 pm (0930 GMT). But the potential of the S-400 fight is a different level that "actually undercuts" the alliance military capability, he said.
The Pentagon has twice pushed back a planned briefing today by senior officials on the subject, and it's unclear when anyone from the USA government will comment.
Turkey has said it was forced to buy the S-400s because Washington refused to supply the American-made Patriot systems to Turkey.
Turkey says the system is a strategic defence requirement, particularly to secure its southern borders with Syria and Iraq.
In a show of bipartisan agreement Friday afternoon, the Republican and Democratic leaders of the Senate Armed Services and Foreign Relations committees issued a joint statement, reinforcing the sense of the Senate that Turkey should suffer consequences for buying the Russian system that North Atlantic Treaty Organisation has long maintained puts its pilots at risk.
It's a Russian-made, long-range, surface-to-air defense system.
Akar said Turkish military personnel were being trained in Russian Federation and in Turkey on how to install and use the system.
American Lawmakers from both sides of the aisle have opposed Turkey having both the S-400 system and F-35 jets.
The US has already halted deliveries of the aircraft to Turkey and suspended the training of Turkish pilots. "Our position regarding the F-35 has not changed, and I will speak with my Turkish counterpart Minister Akar this afternoon", Acting U.S. Secretary of Defense Mark Esper told reporters Friday. Officials told Turkey if the S-400 purchase went through the country would be barred from the F-35 program.