Germany is "very confident" that an agreement on Finland and Sweden joining the Nato alliance can be reached, a source inside the German government has told news agency Reuters.
However, the source considered it unlikely that a consensus could be found before a Nato summit in the Spanish capital Madrid next week, as Turkey continues to block accession talks.
"As nice as it would be to announce concrete steps .. it would not be a catastrophe if it needed a few more weeks," the source said, adding that the German government has not identified any "insurmountable problems" in reaching an agreement.
Nato is hosting talks between Finnish, Swedish and Turkish officials in Brussels on Monday aimed at breaking the deadlock.
Finnish news agency STT reported Foreign Minister Pekka Haavisto (Green) as saying that Finland does not have high expectations for the meeting.
In an interview with AFP, Paul Levin of the Turkey Institute at Stockholm University said that while progress in the talks is possible, it may also prove "very difficult".
"It would require both sides to show real willingness to make some compromises," he said.
Turkish President Recep Tayyip Erdoğan has accused Finland and Sweden of "protecting terrorists" and issued a list of demands that must be met before Ankara will allow accession talks to proceed.
Over the past five years, Turkey has asked Finland to extradite several people it says belong to the Gülen movement and the Kurdistan Workers' Party (PKK) and has also called on Finland and Sweden to lift their arms embargoes on Turkey.
Levin noted that Turkish anger is especially directed at Sweden, even though Sweden considers the PKK to be a terrorist organisation as do other European countries and the EU.
However, Sweden stands out because there are an estimated 100,000 people of Kurdish background living in Sweden, which Levin described as an "influential" minority.
"In that sense, perhaps Turkey is right to focus its spotlight on Sweden," Levin said.