Ankara on Tuesday postponed NATO accession talks with Sweden and Finland, after Turkish President Recep Tayyip Erdogan condemned Stockholm for allowing weekend protests that included the burning of the Koran outside Turkey's Swedish embassy.

But Finland's Foreign Minister Pekka Haavisto said at a press conference in Latvia with his counterpart Edgars Rinkevics: "We are expecting that towards the Vilnius NATO summit the ratification of both Finland and Sweden could go on."

Haavisto acknowledged the protests had caused "hiccups" in Turkey's ratification timetable, but said the Nordic country was "working very closely with Sweden on this issue".

"With Turkey, we don't currently have a timetable", he said, adding that Turkey's elections in mid-May "might be part of the delay".

But "we see a short time slot after the elections and before the Vilnius summit where we hope that the process of ratification could go on", Haavisto said.

All of NATO's 30 members must ratify the joint bids, which they have all done with the exception of Hungary and Turkey. Hungary has said it plans to do so in February.

But Erdogan has dug in his heels ahead of a close presidential election in which he is trying to energise his nationalist electoral base.

- Finnish tanks -

Ankara signed a memorandum of understanding with Finland and Sweden at the end of June. Turkey however says its demands remain unfulfilled regarding the extradition of Turkish citizens it wants to prosecute for "terrorism".

Unlike with Sweden, Turkey has indicated that it has no major objections to Finland's entry into NATO.

While Finland has in the past refused to speculate on joining the alliance without Sweden, on Tuesday hinted it could proceed alone if "something has happened that in the longer term would prevent Sweden from going ahead".

Haavisto, asked about Finland's role in supplying Ukraine with Leopard tanks, said "we are ready to participate in one or another way" providing there was a common package from European countries.

Finland has indicated that it might not send too many of its more than 200 Leopard tanks due to the country's 1,300-kilometre (800-mile) border with Russia.

Helsinki can contribute with "training for the drivers, for the maintenance", said Haavisto.

"We will consider what is the best way for us," he added.