WASHINGTON — Russia will not be allowed to gain a military advantage through its nuclear arsenal, the Pentagon's number two official pledged Thursday.

Bob Work, deputy defense secretary, told lawmakers at the House Armed Services Committee that Russia is "literally playing with fire" through recent actions, which have seen that nation speak openly about increasing its nuclear arsenal.

"Senior Russian officials continue to make irresponsible statements regarding Russia's nuclear forces, and we assess they are doing it to intimidate our allies and us," Work said. "These have failed. If anything, they have really strengthened the NATO alliance solidarity."

He also repeated the US belief that Russia continues to violate the Intermediate-Range Nuclear Forces Treaty, and said the goal is to have Russia return to its limitations. But the US is prepared to act if the regime of Vladimir Putin does not follow that treaty in the future.

"Under any circumstance, however, we will not allow them to gain significant military advantage through INF violations," Work said. "We are developing and analyzing response options for the president and we are consulting with our allies on the best way forward here."

Kingston Reif, director for disarmament and threat reduction policy at the Arms Control Association, said Work may be the first US official to refer to the "escalate to de-escalate" strategy being used by Russia as doctrinal to the Putin government.

Work's comments on Russia stood in opposition to his comments on China. While noting that China is also updating and developing its nuclear arsenal, Work was almost relaxed when discussing the Pacific power.

"We assess that this modernization program is designed to ensure they have a second strike capability and not to seek a quantitative nuclear parity with the United States or Russia," he said.

During questioning, Work said he was unaware of any Chinese espionage attempts to steal nuclear submarine technology.

The US is looking at a major recapitalization of the nuclear force, something that Work and Adm. Sandy Winnefeld, the vice chairman of the Joint Chiefs of Staff, said was an admittedly expensive, but necessary, effort.

"Carrying out this plan is going to be a very expensive proposition and we recognize that," Work said. "It is projected to cost DoD an average of $18 billion a year from 2021 to 2035 in FY16 dollars."

Work later added that the nuclear recapitalization effort would consume about 7 seven percent of the DoD budget during its peak funding in the 2020s.

Included in that effort is the Air Force's next-generation Long Range Strike-Bomber program, the Navy's replacement for the Ohio-class nuclear submarine and upgrades to the nation's ICBM arsenal.

Winnefeld added that without relief from budget caps, funding for the nuclear deterrence mission will have to come from other aspects of the Pentagon budget.

Reif believes the cost of the nuclear recapitalization program should give the government incentive to pause and reconsider its long-term plans.

"Instead of moving forward with an overly ambitious and excessively expensive modernization plan that would recapitalize a US nuclear force that is, by the Pentagon's and the president's own analysis, far larger than US nuclear deterrence needs require, the White House, Pentagon and Energy Department should examine common-sense options for reshaping the arsenal in ways that would save billions and still provide more than adequate nuclear deterrence capabilities," he said. "Such options exist."

Twitter: @AaronMehta