WASHINGTON (Reuters) - The U.S. Senate on Tuesday overwhelmingly backed the expansion of NATO to allow Montenegro to join the alliance, hoping to send a message that the United States will push back against Russian efforts to increase its influence in Europe.

FILE PHOTO: A NATO flag flies at the Alliance's headquarters in Brussels, March 2, 2014. REUTERS/Yves Herman/File Photo

The long-delayed vote was 97-2 in favor of Montenegro’s accession to the North Atlantic Treaty Organization. That was well above the two-thirds majority needed in the 100-member Senate to ratify Montenegro’s membership.

There was no immediate confirmation of whether President Donald Trump would formally deposit the instrument of ratification, the last step in the U.S. ratification process.

However, his administration had supported NATO membership for the tiny Balkan nation, one of Europe’s smallest, despite Trump at times criticizing the alliance as he campaigned for president last year.

While campaigning, Trump accused other NATO members of failing to pay their fair share while adopting a conciliatory tone toward Russia. But as president, Trump has pledged his support for the alliance.

Reuters reported last week that Secretary of State Rex Tillerson wrote to the leaders of the Senate this month to say Montenegro’s membership in NATO was “strongly in the interests of the United States.”

On Tuesday, the only two “no” votes came from Republican Senators Rand Paul and Mike Lee, who had delayed the vote for months by refusing to allow a quick vote. Senate leaders held the more time-consuming roll call vote this week after receiving Tillerson’s letter.

Paul had questioned the wisdom of allowing a country with just 650,000 residents and an army of just 2,000 to join the alliance, saying American taxpayers should not be forced to pay if Montenegro were attacked.

Russia opposes NATO’s enlargement in the western Balkans.

Backers said it was important to support countries like Montenegro to promote western values and push back against Moscow, which Montenegrin officials said was partly behind an alleged plot to overthrow their government during an election in October 2016.

Moscow dismissed that accusation.

“With a nearly unanimous vote, the Senate has sent a clear message that it stands firmly with Montenegro and against the Kremlin’s bullying,” said Senator Jeanne Shaheen, a Democratic member of the Senate Foreign Relations Committee.

All 28 NATO members must ratify Montenegro’s accession in order for the country to join the alliance. Washington is among the last to do so.

(This story corrects vote to 97-2 in second paragraph)