A "reset" in US-Russia relations is now on pause and Moscow likely will be "the primary actor of regional concern," the American general nominated to take over as NATO commander said Thursday.

General Philip Breedlove, President Barack Obama's pick to serve as NATO's next supreme allied commander, described Russia as an "aspirational superpower" and told lawmakers an attempt to forge more cooperative ties with Moscow had faltered for the moment.

"I've described the reset as sort of, on pause," Breedlove told the Senate Armed Services Committee.

"We had made some progress. There were some political changes in Russia and we are now sort of very much slowed down."

In comments that were sure to produce irritation in Moscow, he said the United States needed to renew efforts to improve relations but said it had to be a mutually beneficial arrangement.

"I do agree with your concern that this not become a one-way street, and that we just give, give, give. I think that the principle of reciprocity is how we need to think about our work with Russia," he said.

The United States and Russia saw a warming of ties during Obama's first term, but ties frayed after Vladimir Putin returned as president last year.

Breedlove suggested Russia would be the main source of instability in the region and that Washington and NATO would need to reassure partners within Moscow's orbit.

"Russia will remain the primary actor of regional concern through 2020 by virtue of its geographic position, natural resource wealth, military forces, and desire for regional influence," the four-star general said in written testimony to the senate committee.

"The US and NATO will need to continue to assure our Allies and partners, who live in the Russian self-declared 'sphere of privileged influence,' of our resolve."

He called for renewing efforts to cooperate with Russia on missile defenses for Europe, an issue that has remained a source of disagreement with Moscow viewing the project as a threat.

The general added Russia should not be thought of as an "enemy" but as a partner.

If confirmed by the Senate, Breedlove will succeed Admiral James Stavridis as NATO commander.

The former head of NATO-led forces in Afghanistan, General John Allen, had initially been chosen to take the post of alliance commander. But after highly-publicized allegations over emails to a Florida woman, Allen withdrew his name even though he was cleared of any wrongdoing.