By Andrius Sytas

VILNIUS (Reuters) -Lithuania's president urged NATO leaders to be bolder in addressing Ukraine's push for membership at a summit in his country next week, saying this would boost Kyiv's battlefield performance while Moscow would see any caution as weakness.

In an interview with Reuters, President Gitanas Nauseda advised NATO allies to disregard fears that bringing Ukraine into the U.S.-led military alliance would provoke Russia, which invaded Ukraine on Feb. 22, 2022.

"We should not hesitate to take bolder decisions because otherwise the Putin regime will decide that the Western allies are too weak, (that they should be) pushed to the corner and they will surrender", Nauseda said on Monday.

"Our stronger wording on Ukraine's (membership) perspective would for sure increase the fighting spirit of Ukrainian soldiers on the battlefield. And this is very important", he added.

Ukraine has been pressing NATO to declare at the July 11 and 12 summit that Kyiv would join the alliance soon after the end of the war, and to set out a roadmap to membership.

But other members such as the U.S. and Germany have been more cautious, wary of any moves they fear could take the alliance closer to an active war with Russia, which has long seen NATO's expansion as evidence of Western hostility.

Nauseda told Reuters that a promise of an easier path to NATO membership after the war and more military support pledges could be offered to Ukraine at the next week's gathering.

"We have some countries which are cautious about the stronger wording on Ukraine's perspective. But I already see some shift in the minds of their leaders", Nauseda said.

"We all understand that right now, in the midst of the war, Ukraine is not able to join NATO immediately. We understand that. Ukrainians understand that. But we need to create procedures, how to proceed ... so there is no wasting of time if the war is over and victory is on Ukrainian side".

Nauseda said he expects Ukrainian President Volodymir Zelenskiy to show up in Vilnius, despite his warnings that he sees "no point" in going if Kyiv is not given a "signal" at the meeting: "I hope he will be here and he will play an important role in the decision making in Vilnius".

Several countries are readying an "additional portfolio of (military support) obligations" for Ukraine, to announce at the NATO summit, Nauseda said.

GERMAN DEPLOYMENT

However the possibility of Sweden being accepted into NATO in Vilnius is getting "complicated", and the chances it will be able to join at the summit are going down "with each additional day", Nauseda said.

Sweden applied to join NATO following the invasion, but Turkey and Hungary have so far blocked ratification.

Nauseda said he expects Germany to deploy 4,000 troops in Lithuania, with families and equipment, by about 2026-2027, in gradual increases. The deployment was pledged by German Defence Minister Boris Pistorius last week, and Canada is taking decision to incrase its troops in Latvia, Nauseda said.

The Lithuanian president said the host country expects provocations, during and after the summit, along its border with Belarus, where the Russian Wagner private militia has been offered refuge after its failed coup.

"You can expect that the (Wagner) fighters can emerge at the border as migrants, as citizens of Belarus... we can expect a lot of provocations there, especially ahead of Vilnius summit or afterwards. And I think this is a very important element of our security", said the president.

(Reporting by Andrius Sytas in Vilnius, Editing by William Maclean)