WASHINGTON — The US Senate voted overwhelmingly Monday to advance the approval of Montenegro as the newest member of NATO, in what supporters of the alliance’s expansion argue would send a stern message to Russia.

The procedural step, which advanced on a 97-2 vote, sets up a final approval in the chamber in the coming days.

President Donald Trump’s administration has encouraged lawmakers to back the small Balkan nation’s bid.

"It is strongly in the interests of the United States that Montenegro’s membership in NATO be ratified," Secretary of State Rex Tillerson told Senate leaders in a March 7 letter.

To date, 25 of NATO’s 28 members have ratified Montenegro’s accession, a country of 620,000 people seen as a geostrategic ally.

The North Atlantic Treaty Organisation holds its summit on May 25 in Brussels, where Trump will use the opportunity to reaffirm Washington’s strong commitment to the alliance, according to the White House.

The Kremlin is opposed to Montenegro’s accession, calling it a "provocation" that would reinforce the pro-Western military alliance’s presence in the Balkans.

The US vote comes days after a Montenegrin special prosecutor accused "Russian state bodies" of involvement in an alleged coup plot during Montenegro’s election last October.

Moscow branded the accusation "absurd".

As with all international treaties, a two-thirds majority is required for final Senate approval. Success is highly likely.

Republicans Rand Paul and Mike Lee voted against the measure.

Paul warned Washington against spreading itself too thinly when its military is involved in Iraq, Syria, Libya and Yemen, and said Montenegro in NATO will antagonise Russia while doing "nothing" to advance US national security.

"Most Americans can’t find Montenegro on a map," Paul said in a sharply worded Senate speech. "Are you willing to send your kids there to fight?"

Besides the United States, the Netherlands and Spain have yet to ratify Montenegro’s membership. — AFP