Sweden could still become a NATO member by summer, NATO chief Jens Stoltenberg told POLITICO on Thursday as Finland moved ahead on its own to join the military alliance.

The two Nordic countries initially applied to join NATO together last year, but their fates diverged Thursday after Turkey ratified Finland’s bid while leaving Sweden behind — the product of a lingering dispute over the country’s support for Kurdish groups and limitations on arms exports.

Stoltenberg insisted in an interview that Sweden could still get its own green light after Turkey’s May elections. Turkey’s relationship with Sweden has grown especially contentious ahead of the elections, following a Quran-burning protest in Stockholm earlier this year.

“My aim remains that after the Turkish elections, but before the Vilnius summit, we can also have the ratification of Sweden,” the secretary-general said from NATO headquarters in Brussels, referencing the alliance’s annual gathering on July 11.

He did not say, however, if that would require a change in governments. Long-time Turkish leader Recep Tayyip Erdoğan, who is regularly accused of democratic backsliding, is facing a serious threat to his power for the first time in years.

Stoltenberg stressed that the decision is ultimately up to Turkey. Hungary has also withheld ratification, but Turkey is seen as the ultimate roadblock for Sweden.

“We speak about sovereign national parliaments, and of course, I cannot provide any guarantees on behalf of them,” he said.

The NATO chief argued that even getting Finland into NATO after months of delays — also the result of Turkey-led objections over similar issues — shows the military alliance is working amid Russia’s war in Ukraine.

Finland’s final ratification “demonstrates that NATO’s door remains open,” he said. Russian President Vladimir Putin, he added, got “the opposite of what he wanted — and Finland will make NATO stronger.”

If both Finland and Sweden join the alliance, Stoltenberg noted, 96 percent of the European Union’s population will soon live in a NATO country.

“Today is an historic day,” he proclaimed.

But probed about the lagging Swedish bid, which has fueled a degree of frustration within the alliance, the secretary-general expressed hope that Turkey could sign off on Sweden’s membership between the May 14 election and the July summit.

Stoltenberg underscored that, in his view, Stockholm has done its part to address Ankara’s concerns.

“Sweden has met their obligations under the trilateral memorandum that was agreed,” he said, referencing a deal Ankara struck with both Helsinki and Stockholm that spurred policy changes in both countries.

“There were hard negotiations, but Sweden has proven that they are stepping up their cooperation with Turkey, fighting terrorism, exchanging more intelligence, information — and there are no restrictions on arms exports” from Sweden to Turkey, he added.

The secretary-general also reiterated that even though Sweden is not yet a member of the club, it is not alone.

“Sweden is in a total different situation, and much more secure now than before they applied,” he said.

“They’re now sitting at the NATO table,” he said, pointing out that the alliance has boosted its presence in the region and some allies have given Sweden security assurances.

“I will work hard to get the ratification of Sweden in place as soon as possible,” Stoltenberg said. “But no, it’s not as if in this meantime Sweden is alone, without any friends, without any security.”

“It’s inconceivable,” the secretary-general said, “that we will not react if there’s any military threat.”