The national security advisers for US President Joe Biden and Turkish leader Recep Tayyip Erdogan addressed points of tension between the two Nato allies in an hour-long call on Monday.
It was the first time US National Security Adviser Jake Sullivan spoke to his Turkish equivalent, Ibrahim Kalin, since Mr Biden took office last month.
“Mr Sullivan underscored the Biden administration’s desire to build constructive US-Turkey ties, expanding areas of co-operation and managing disagreements effectively,” National Security Council spokeswoman Emily Horne said.
“He conveyed the administration’s intention to strengthen transatlantic security through Nato, expressing concern that Turkey’s acquisition of the Russian S-400 surface-to-air missile system undermines alliance cohesion and effectiveness.”
After more than a year of stalling, former president Donald Trump imposed sanctions on Turkey in December for buying the S-400, as required under a Russia sanctions law that Congress passed in 2017.
The sanctions include a ban on all US export licences and authorisations on Ankara’s military procurement agency, and an asset freeze and visa restrictions on several of its officers.
Before that, the Trump administration had expelled Turkey from the F-35 fighter jet co-production programme, fearing the powerful S-400 radar system would allow Russia to spy on the stealth fighters.
Turkey’s state-run Anadolu Agency reported that “both officials highlighted the importance of strengthening Turkish-US ties in the coming period, staying in close contact and [keeping] dialogue channels open for constructive co-operation".
But the report also noted that Mr Kalin called for “a new perspective regarding issues such as Turkey’s S-400 procurement, its removal from the F-35 fighter jet programme and US support to YPG, which Turkey views as the Syrian offshoot of the PKK [Kurdistan Workers' Party] terror group".
Despite Turkish opposition, the US military backed the Syrian Kurds as part of its campaign to defeat ISIS.
Several hundred US troops are in north-east Syria, which falls under the control of the Kurdish YPG, or the People’s Protection Units.
On a more positive note, the White House said: “Mr Sullivan welcomed the resumption of exploratory talks between Turkey and Greece, and he expressed support for plans by UN Secretary General [Antonio] Guterres to resume talks on Cyprus.”
Ankara and Athens agreed to hold talks last month regarding competing maritime claims in the Eastern Mediterranean.
Tension boiled over last year when Ankara sent warships to escort its vessels exploring for hydrocarbons off the disputed island of Cyprus, prompting a naval stand-off with Greece, France and Cyprus.
The Anadolu report was also optimistic about the talks with Greece, saying they were “expected to contribute to peace and stability in the Eastern Mediterranean".
Other areas of agreement included the Covid-19 pandemic and climate change.
Mr Kalin welcomed Mr Biden’s decision to return the US to the Paris climate accord.
Mr Sullivan also “underscored the Biden administration’s broad commitment to supporting democratic institutions and the rule of law".
Turkish police recently launched a violent crackdown on student protesters at the Bogazici University in Istanbul, after Mr Erdogan appointed a conservative rector to lead the institution.
The president also floated the idea of drafting a new constitution on Monday, shortly after his political allies began calling for a rewrite to ban the pro-Kurdish People’s Democratic Party.