VILNIUS, July 10 - NATO’s summit will begin Tuesday with fresh momentum after Turkey withdrew its objections to Sweden joining the alliance, a step toward the unity that Western leaders have been eager to demonstrate in the face of Russia’s invasion of Ukraine.

The decision by Turkish President Recep Tayyip Erdogan is a significant move toward Sweden’s membership and it will alleviate tension in Vilnius, Lithuania’s capital, The Associated Press reported.

“This is a historic day,” NATO Secretary-General Jens Stoltenberg said late Monday as he announced the agreement following days of intensive meetings.

As part of the deal, Erdogan said he would ask Turkey’s parliament to approve Sweden joining NATO. Hungarian Prime Minister Viktor Orban is expected to take a similar step.

The outcome is a victory for U.S. President Joe Biden as well, who has touted NATO’s expansion as an example of how Russia’s invasion of Ukraine has backfired on Moscow. Finland has already become the 31st member of the alliance, and Sweden is on deck to become the 32nd.

Biden arrived in Vilnius on Monday evening and was scheduled to meet with Erdogan on Tuesday evening. Biden was also attending a meeting of the North Atlantic Council, of which Sweden is a member, in the afternoon.

NATO leaders will still have other big questions to address at their summit, particularly Ukraine’s desire to join NATO. The Baltic states — including Lithuania, which is hosting the event — have pushed for a strong show of support and a clear pathway toward membership for Ukraine.

The United States and Germany have resisted that, and Biden said last week that Ukraine wasn’t ready to join. Members of NATO, he told CNN, need to “meet all the qualifications, from democratization to a whole range of other issues,” a nod toward longstanding concerns about governance and corruption in Kyiv.

In addition, some fear that bringing Ukraine into NATO would serve more as a provocation to Russia than as a deterrence against aggression.

Stoltenberg wrote in Foreign Affairs on Monday that the alliance would “upgrade our political ties” by forming a NATO-Ukraine Council, which would be “a platform for decisions and crisis consultation.”

President Volodymyr Zelenskyy is expected to attend the summit on Wednesday. He plans to meet with Biden while there, according to two administration officials who spoke on condition of anonymity to discuss plans that have not been announced.

Stoltenberg reiterated that Ukraine will eventually become a member of NATO, a commitment made in 2008 under President George W. Bush. The NATO chief did not outline more specifics.

However, Ukrainian Foreign Minister Dmytro Kuleba said NATO had agreed to forgo requiring a “membership action plan,” a decision that he said “shortens our path to NATO.” (ap/ez)