Sweden’s Prime Minister Ulf Kristersson on Wednesday secured a show of support from US President Joe Biden for his country’s stalled bid to join NATO.

The two leaders met to sketch a last-ditch attempt at clearing the path for the Nordic nation’s accession ahead of the alliance’s summit in the Lithuanian capital Vilnius next week. The bid is being held up by Turkey, which accuses Sweden of not clamping down hard enough on groups that the Turkish government views as terrorist.

“The United States fully, fully, fully supports Sweden’s membership in NATO,” Biden said, reiterating a long-held stance. “And the bottom line is simple: Sweden is going to make our alliance stronger and has the same value set that we have in NATO. And we’re anxiously looking forward to your membership.”

Turkey has held off on ratifying Sweden’s application for more than a year, with Hungary in tow. Allies, including the US, have sought to put pressure on President Recep Tayyip Erdogan to approve the Nordic nation’s entry.

A key point of leverage for the US could be a Turkish bid to purchase American-made F-16 fighter jets, a transaction that requires congressional approval. But on Wednesday Turkish official rebuffed linking the two issues.

Read More: Turkey Snubs US Pressure on F-16s as Biden Meets Swedish Premier

Sweden argues that it has fulfilled all obligations under an agreement hammered out a year ago at the alliance’s summit in Madrid. The country also meets the membership criteria set out by the North Atlantic Treaty Organization.

Earlier this week, Erdogan again lashed out at Sweden for allowing sympathizers of the terrorist-designated Kurdish PKK group to display the organization’s symbols at protests in Stockholm, and for allowing a public burning of the Koran near the main mosque in the center of the Swedish capital.

“These are hate crimes that feed on hostility to Islam,” Erdogan said on Monday. “It is much worse that this hate crime can be committed under police protection.”

The comments appeared to put a damper on any hopes of a breakthrough in the week before leaders of NATO countries and Sweden gather for the high-stakes meeting in Vilnius. Sweden’s foreign minister Tobias Billstrom, who traveled with Kristersson to Washington, will meet his Turkish and Finnish counterparts at NATO’s headquarters in Brussels on Thursday, seeking to make progress ahead of the July 11-12 summit.

While Turkey in March approved the bid by fellow applicant Finland, its refusal to let neighboring Sweden join may complicate NATO’s plans to defend its expanded eastern border with Russia and stymie ambitions of boosting the alliance’s presence in the Arctic region. For Finland, it means uncertainty over supply routes and lack of depth to its defenses.

For Sweden, the delay, while manageable for now, will start to get problematic if it means the Nordic nation is left out of NATO’s defense planning for an extended period of time, according to Micael Byden, commander in chief of Sweden’s Armed Forces.

“Just look at the map — not being able to incorporate Sweden’s territory and its armed forces in concrete military plans will make it harder for NATO, and we would not be able to access what we need in terms of plans, management and cryptographic systems,” Byden said in an interview last week on the Swedish island of Gotland. “We would be on the sideline, and that makes things difficult.”

--With assistance from Akayla Gardner, Alisa Parenti and Jordan Fabian.