In a further show of military might amid already high tensions with the West, Russia announced it is planning to send long-range bombers on patrols over North American waters, including the Gulf of Mexico.

Russian defense minister Sergei Shoigu made the announcement amid fresh NATO accusations of Russia sending troops and tanks into eastern Ukraine to prop up pro-Russian separatists. NATO also accuses Russia of flying "provocative" routes into European airspace.

"In the current situation, we need to secure our military presence in the western part of the Atlantic, eastern part of the Pacific oceans and the waters of the Caribbean and Gulf of Mexico," Shoigu said.

The Russian planes will also conduct reconnaissance missions and monitor foreign powers' military activities and communications, according to Shoigu.

United States defense officials however downplayed the planned flights as routine training in international airspace.

"The Russians have patrolled in the Gulf (of Mexico) in the past, and we've seen the Russian Navy operate in the Gulf of Mexico. These are international waters," Pentagon spokesman Colonel Steve Warren said.

"It's important that the Russians conduct their operations safely and in accordance with international standards," he added.

But a senior US official who spoke on condition of anonymity told the Associated Press that Russia has never before flown bomber patrols over the Gulf of Mexico, even during the Cold War. Other types of aircraft however, including surveillance planes and anti-submarine aircraft have previously flown flights over the Gulf of Mexico, the official said.

Sharp rise in military encounters

Russian long range bomber patrol flights stopped in the wake of the economic meltdown following the collapse of the Soviet Union, but were resumed under Russian president Vladimir Putin and have become increasingly frequent. NATO has reported a spike in Russian military flights over the Atlantic ocean as well as the Black, Baltic and North seas.

Experts say the ramp up in military activity is cause for concern.

"The more instances you have of NATO and Russian forces coming close together, the more chance there is of having something bad happening, even if it's not intentional," said Ian Kearns, director of the London-based European Leadership Network (ELN).

According to the ELN, military incidents with Russia have risen sharply since the nation annexed Crimea. In a report issued Monday, the think tank listed nearly 40 incidents, three of which carried a "high probability" of causing casualties or triggering a military confrontation.

The incidents listed include a large scale Swedish hunt for a suspected Russian submarine, a narrowly avoided collision between a Russian surveillance plane and a civilian airliner, and the Russian abduction of an Estonian intelligence officer.

bw/jm (AP, Reuters)