President Recep Tayyip Erdoğan told NATO Secretary-General Jens Stoltenberg by phone that Turkey's security concerns regarding Sweden and Finland's membership bids were based on just and legitimate grounds, Erdoğan’s office said late Friday.

"Both countries should make it clear that they have stopped supporting terrorism, that they have lifted sanctions against Turkey, and that they are ready to show alliance solidarity," Erdoğan was cited as telling Stoltenberg in the call.

NATO Secretary General Stoltenberg, for his part, drew attention to the necessity to fulfill the expectations of Turkey, an important ally.

Later, the NATO chief said on Twitter that he had a constructive phone call with Erdoğan.

"#Türkiye is a valued Ally & we commend their efforts to broker a deal over food security. We addressed #Finland's and #Sweden's #NATO accession & will continue our dialogue," Stoltenberg noted.

Separately, the alliance chief had a meeting with Finnish Prime Minister Sanna Marin in Washington and discussed the Nordic countries' NATO bids, as well as the "need to address" Turkey's concerns.

Ankara continues to protest Stockholm and Helsinki's membership bids to join the trans-Atlantic alliance, maintaining both countries have supported and provided a safe haven to terrorists, including members of the YPG/PKK terrorist group and others.

Sweden and Finland formally applied to join NATO on May 18, a decision spurred by Russia's war on Ukraine, which began Feb. 24. But Turkey, a longstanding member of the alliance, has voiced objections to their membership bids, criticizing the countries for tolerating and even supporting terrorist groups such as the YPG/PKK and the Gülenist Terror Group (FETÖ), the group responsible for a failed 2016 coup in Turkey.

All membership applications must be met by unanimity in the 30-member alliance to be successful.