MOSCOW (Reuters) - Russia said on Wednesday it planned to send long-range bombers on flight patrols over North American waters, including the Gulf of Mexico, but the Pentagon played down Moscow's mission as routine training in international airspace.

The announcement by Defense Minister Sergei Shoigu came just days after NATO singled out some Russian incursions into European airspace, including more complex formations of aircraft flying more "provocative" routes.

Shoigu said flights along the border of the Russian Federation and over the Arctic Ocean were foreseen as part of training for long-range operations, according to state agency Itar Tass.

"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," he added.

At the Pentagon, spokesman Colonel Steve Warren said every nation had the right to operate in international waters and 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," Warren said.

"It’s important that the Russians conduct their operations safely and in accordance with international standards."

Relations between Moscow and the West have plummeted over the crisis in Ukraine, where Kiev faces a rebellion by pro-Russian separatists in the east of the country.

Bomber patrol flights, a Cold War-era practice, were cut back after the fall of the Soviet Union but President Vladimir Putin revived them in 2007.

(Reporting by Thomas Grove; Additional reporting by Phil Stewart in Washington; Editing by Ralph Boulton and Lisa Shumaker)