Turkey and Hungary are the only NATO countries still to ratify the applications, which must be accepted by all 30 existing members of the military organisation.

Ankara has held up the process and is pushing a list of demands, including that Sweden expel dozens of mostly Kurdish residents it suspects of ties to separatist militants.

A statement from NATO said that "participants welcomed the progress that has been made" on a three-way deal struck last year aimed at satisfying Turkey's complaints.

"They further agreed that rapid ratifications for both Finland and Sweden would be in everyone's interest, and that their membership will strengthen the alliance," NATO said after the talks chaired by Secretary General Jens Stoltenberg.

The statement said the three countries agreed to meet again in the same format ahead of a NATO summit in Vilnius in July.

Swedish negotiator Oscar Stenstrom said there had been "a small step forward".

"Our counterparts have accepted and recognised that there has been progress in the measures we have taken," he said.

"The positive aspect today is that we have agreed that the discussions will continue."

The latest meeting came after Ankara had earlier suspended negotiations in outrage at protests in January that included the burning of the Koran outside its embassy in Stockholm.

As part of its efforts to assuage Ankara, the Swedish government announced Thursday it wants to ban more activities linked to extremist groups as part of a text aimed at toughening its anti-terrorism law.

Both Finland and Sweden dropped their decades-long policies of military non-alignment and applied to join the alliance last May in the wake of Moscow's invasion of Ukraine.

Turkey has raised the prospect of accepting Finland without letting Sweden's application through.

NATO officials are broadly against splitting up the bids, but increasingly accept the possibility that Helsinki may join first.

Turkish President Recep Tayyip Erdogan has dug in his heels on Sweden as he heads into a close presidential election in which he is trying to energise his nationalist electoral base.