HELSINKI -- The Finnish president said in an interview published Saturday that he trusts that Finland and Sweden will be admitted into NATO by July, and hinted that he wants the United States to put pressure on Turkiye to approve their membership bids.

If the issue drags on, the entire process of admitting new members into the military alliance will become questionable, President Sauli Niinisto said in an interview with the Finnish news agency STT.

"If it doesn't happen by the Vilnius meeting, why should it happen afterwards?" Niinisto said.

Lithuania is set to host a NATO summit in the Baltic nation's capital on July 11-12.

NATO requires unanimous approval from its existing members to admit new ones. Turkiye and Hungary are the only nations in the 30-member military alliance that haven't formally endorsed Sweden and Finland's accession.

While Hungary has pledged to do so in February, Turkiye hasn't indicated willingness to ratify the two countries' accession any time soon. Niinisto stressed that the final Turkish decision is up to Turkish President Recep Tayyip Erdogan.

"I think that under no circumstances will he allow himself to be influenced by any public pressure," Niinisto said. " But if something opens up during the bilateral talks between Turkiye and the United States, it might have an impact."

Turkiye has been holding off approving Sweden and Finland's membership into NATO as it has been infuriated, among other things, by a recent series of demonstrations in Stockholm by activists who have burned the Quran outside the Turkish Embassy and hanged an effigy of Erdogan.

In January, Ankara indefinitely postponed a key meeting in Brussels that would have discussed the two Nordic countries' entry into NATO.

Niinisto said that Finland and Sweden heard many encouraging statements from NATO last spring -- the Nordic duo had stated their intention to join NATO in May -- about smooth and painless progress of membership.

He said that did not happen, adding that the delay isn't only a headache for the two applicant countries.

"I can see that this has already become a problem for NATO. Clearly, NATO countries have also been surprised," Niinisto said.