By Gwladys Fouche and Sabine Siebold

OSLO (Reuters) -NATO Secretary-General Jens Stoltenberg said on Thursday he would soon travel to Turkey to discuss Sweden's NATO membership, in a bid to close a process that has been delayed due to objections from member countries Turkey and Hungary.

Speaking during a two-day meeting of NATO foreign ministers in Oslo, Stoltenberg said he had spoken earlier this week to Tayyip Erdogan, who at the weekend won re-election as Turkey's president.

"I will also travel to Ankara in the near future to continue to address how we can ensure the fastest possible accession of Sweden," Stoltenberg told reporters.

With Turkish elections over and Erdogan winning another term as president, some NATO foreign ministers expressed optimism Ankara would now lift its objections to Stockholm's bid to join the military alliance.

"Now that Turkish elections are over, it is important that Turkey goes on with the ratification process," said Finnish Foreign Minister Pekka Haavisto.

Turkey ratified Finland's NATO accession in March, but says Sweden harbors members of militant groups it considers terrorists.

Timing-wise, several foreign ministers expressed confidence Sweden could become a member before, or at, a NATO summit in Vilnius, Lithuania, in July.

"There is a very high expectation that the Swedish flag will be raised (in Vilnius)," said Lithuanian Foreign Minister Gabrielius Landsbergis.

Sweden, invited to Oslo, stressed again it had fulfilled all the conditions set to become a member of the military alliance.

"We have fulfilled all our commitments," Swedish Foreign Minister Tobias Billstrom told reporters.

"It is time for Turkey and Hungary to start the ratification of Swedish membership to NATO."

(Reporting by Gwladys Fouche and Sabine Siebold, editing by Terje Solsvik and Kim Coghill)