By Ezgi Erkoyun and Kanishka Singh
ISTANBUL/WASHINGTON (Reuters) -U.S. President Joe Biden expressed a desire to see Sweden join NATO "as soon as possible" in a phone call with Turkish President Tayyip Erdogan in which they discussed Sweden's bid to become a member of the Western alliance, the White House said on Sunday.
Turkey, along with Hungary, has been a stumbling block to Sweden's bid, which requires unanimous approval by all NATO members.
Erdogan told Biden that Stockholm has taken steps in the right direction for Ankara to ratify its bid, referring to an anti-terrorism law, but said these steps were not useful as Kurdistan Workers Party (PKK) supporters continued to hold demonstrations in Sweden, the Turkish presidency's communications directorate said separately on Sunday.
Biden "conveyed his desire to welcome Sweden into NATO as soon as possible," the White House said in a statement.
The leaders agreed to meet face-to-face in Vilnius, Lithuania, at an upcoming NATO summit and discuss bilateral relations and regional issues in detail, the Turkish presidency also said.
On Thursday, Sweden failed to convince Turkey to lift its block on Stockholm's path to NATO membership in a foreign minister-level meeting, as Ankara requested more action in the fight against terrorism.
NATO Secretary-General Jens Stoltenberg said he would convene a meeting between Erdogan and Swedish Prime Minister Ulf Kristersson in Vilnius on Monday.
Sweden and Finland applied for NATO membership last year, abandoning policies of military non-alignment that had lasted through the decades of the Cold War in response to Russia's invasion of Ukraine.
While Finland's NATO membership was green-lighted in April, Turkey and Hungary have yet to clear Sweden's bid. Stockholm has been working to join at next week's NATO summit in Vilnius.
During their call, Biden and Erdogan also discussed the delivery of F-16 fighter jets to Turkey, and Ukraine's aim to join NATO, according to the Turkish presidency's readout.