US President Joe Biden has urged Finland and Sweden to join NATO in a jibe at Russia.
Finland and Sweden say they have been spurred into joining NATO by Russia's invasion of Ukraine, reversing generations of
military non-alignment to bring about the biggest shakeup in European security for decades.
President Joe Biden hosted Swedish Prime Minister Magdalena Andersson and Finnish President Sauli Niinistö, a chance for Washington to demonstrate that Russia's invasion has backfired, bringing about the very expansion of NATO that Moscow has said it was fighting to halt.
White House national security adviser Jake Sullivan said: "This is a historic event, a watershed moment in European security.
"Two nations with a long tradition of neutrality will be joining the world's most powerful defensive alliance."
Biden cheered the "momentous" day, giving his strong support for the two "great democracies'' to "join the strongest most powerful defensive alliance in the history of the world."
"They meet every NATO requirement and then some," Biden said, adding he is submitting paperwork today to the US Congress for speedy approval once NATO approves their accession.
But Turkey has surprised its allies by objecting to the move, accusing the two Nordic states of harbouring Kurdish
militants.
"We will continue our policy in a determined way.
"We have told allies that we will say no to Finland and Sweden's NATO membership," Erdogan said in an interview with students late on Wednesday.
"NATO is a security alliance and we cannot accept terrorists to be in it."
Washington has so far played down the Turkish objections, saying it expects the issues to be resolved.
The past week has seen Russia secure its biggest victory since the invasion began in February, with Kyiv announcing it had ordered its garrison in a steelworks in Mariupol to stand down, after a nearly three-month siege of the city.
The ultimate outcome of the bloodiest battle in Europe for decades has remained publicly unresolved, with no confirmation of the fate of hundreds of Ukrainian defenders.
Moscow said on Thursday that 1,730 Ukrainian fighters had surrendered so far, including 771 in the past 24 hours.
Ukraine, which says it aims to secure a prisoner swap, has declined to say how many were inside the plant or comment on the fate of the rest since confirming that just over 250 had surrendered in the initial hours after it ordered them to yield.
The Switzerland-based International Committee of the Red Cross said it has registered hundreds of prisoners from the plant now held by Russia, but it has not given a precise number.
The leader of Russian-backed separatists in control of the area said nearly half of the fighters remained inside the steelworks, where underground bunkers and tunnels had protected them from weeks of Russian bombardment.
"More than half have already left - more than half have laid down their arms," Denis Pushilin told the Solovyov Live internet television channel.
He added: "Let them surrender, let them live, let them honestly face the charges for all their crimes."
The wounded had been given medical treatment while those who were fit had been taken to a penal colony and were being treated well, he said.
Ukrainian officials say they cannot comment publicly on the fate of the fighters while negotiations are under way to rescue them.
Russia denies that it agreed to a prisoner swap.
Many of the Azovstal defenders belong to a Ukrainian unit with far-right origins, the Azov Regiment, which Moscow calls Nazis and says must be prosecuted for crimes.
