The man nominated to be the US military’s top officer said that Russia now poses the greatest threat to US national security and its behavior is "nothing short of alarming.

The man nominated to be the US military's top officer said that Russia now poses the greatest threat to US national security and its behavior is "nothing short of alarming.

General Joseph Dunford-- who is currently the commandant of the US Marine Corps -- told senators at his confirmation hearing that the Pentagon nevertheless needed to maintain some kind of military-to-military relationship with Moscow.

"Russia presents the greatest threat to our national security," Dunford, who would replace General Martin Dempsey as chairman of the US Joint Chiefs of Staff, told the Senate Armed Services Committee.

Dunford also cited China, North Korea and the Takfiri group, ISIL (so-called Islamic State in Iraq and Levant) as threats to US national security.

Relations between the United States and Russia have been rocky since Moscow annexed Ukraine's Crimea region after a national referendum last year.

The chairman of the Joint Chiefs of Staff acts as the top military advisor to the US president and the secretary of defense.