The Kremlin on Friday, May 20 condemned NATO's membership invitation to Montenegro, saying the step risked fuelling geopolitical tensions in Europe, Reuters reports.

"In general, our stance is that NATO's further expansion is a negative process," Kremlin spokesman Dmitry Peskov told a conference call with reporters. "This process yields nothing from the point of view of European security."

"On the contrary, this process risks further increasing tensions on the continent."

NATO formally invited Montenegro to become its 29th member on Thursday, a decision that must still be approved by the U.S. Senate, as well as the military alliance’s other 27 parliaments and Montenegro’s own parliament.