Talks being held at the bilateral level and not under NATO supervision, Turkish presidential spokesman Ibrahim Kalin says.
Turkey and the US have begun talks to resolve their differences in the military sector, especially on the S-400 missile system and F-35 fighter jets, the Turkish presidential spokesman said on Friday.
In an interview aired on public broadcaster TRT, Ibrahim Kalin said the talks are being carried out at the bilateral level and not under NATO supervision.
"The two presidents appointed me and [US National Security Advisor] Robert O'Brien at the White House meeting. We are starting to work on it as I speak," said Kalin.
"S-400 system can be used independently without being integrated into the NATO defence system," he said, adding "There is no pullback [from the systems]. Turkey will activate the S-400s."
Kalin also said Russian President Vladimir Putin was expected to visit Ankara in the first half of January.
"There might be a ceremony for the completion of the Turk Stream project. Also, bilateral relations and regional issues will be discussed," he added.
Row over S-400s
Turkey's acquisition of the advanced Russian S-400 air-defence system prompted Washington to remove Ankara from the F-35 fifth-generation joint strike fighter programme in July.
The US maintains that the system could be used by Russia to covertly obtain classified details on the jet and is incompatible with NATO systems.
Turkey, however, says that the S-400 would neither be integrated into NATO systems nor pose a threat to the alliance.
On Thursday, US Senate Foreign Relations Chairman Jim Risch said he is pausing sanctions on Turkey.
"Probably, it's best we don't pass a sanctions bill at this moment," Risch told reporters on Thursday in his office, referring to the negotiations between the US and Turkey.
Risch attended Wednesday's meeting between US President Donald Trump and Turkey's President Recep Tayyip Erdogan in the Oval Office along with some other Republican senators.
He called the meeting "very therapeutic."
"President Erdogan isn't completely there yet, but it's a give-and-take proposition," he said. "He is very clearly aware of the decisions that he has to make, and the repercussions for those decisions."