Montenegro's bid to join NATO faces US Senate test

Ratification of the tiny Balkan nation's admission into the alliance is expected to clear a procedural hurdle in the Senate on Monday, setting the stage for a final vote later this week.

Secretary of State Rex Tillerson has pressed the Senate to act quickly, telling Senate leaders earlier this month that the chamber's approval should come ahead of a summit scheduled for May that will include NATO heads of state and government.

"Montenegro's participation in the May NATO summit as a full member, not an observer, will send a strong signal of transatlantic unity and that no third parties have veto power over NATIO decisions," Tillerson wrote in the letter to Senate Majority Leader Mitch McConnell, R-Ky., and Minority Leader Chuck Schumer, D-N.Y.