US accuses Russia's Vladimir Putin of breaching Cold War-era treaties

 The US on Friday accused Russian President Vladimir Putin of breaching Cold War-era treaties by developing a new generation of "invincible" weapons and said American military was fully prepared to defend the country.

"President Putin has confirmed what the US government has known for a long time but that Russia has denied prior to this," White House Press Secretary Sarah Sanders said.

She said Russia has been developing destabilising weapons systems for over a decade in direct violations of its treaty obligations.

Her comments came hours after President Putin announced that Russia has developed a number of advanced weapons systems, including a nuclear-powered cruise missile, which make all US capabilities aimed at undermining the Russian nuclear deterrent obsolete.

Sanders said US President Donald Trump understands the threats facing America and its allies in this century and is determined to protect the homeland and preserve peace through strength. "US defense capabilities are, and will, remain second to none," she told reporters.

"And now, because of the new defence budget of USD 700 billion, our military will be far stronger than ever. As President's Nuclear Posture Review made clear, America is moving forward to modernise our nuclear arsenal and ensure our capabilities are unmatched, Sanders said.

The State Department expressed concern over the Russian video, along with the Putin speech, which targeted the US.

"It is certainly concerning to see your government, to see your country, put together that kind of video that shows the Russian Government attacking the US. That's certainly a concern of ours. I don't think that that's very constructive, nor is it responsible," State Department Spokesperson Heather Nauert told reporters at a separate news conference.

The Pentagon said it is not surprised by Putin's statement and is fully prepared to defend the country.

"They know very well that it's not about them. Our missile defense has never been about them. We need to ensure we have a credible nuclear deterrent, and we are confident that we are prepared to defend this nation no matter what," Pentagon Chief Spokesperson Dana White told reporters.

Congressman Mac Thornberry, Chairman of the House Armed Services Committee, said that for too long presidents of both parties have let all sorts of persistent Russian aggression go unanswered, whether violations of multiple treaties, election meddling, planting fake news stories, or invading sovereign countries.

"It took six years for the Obama administration to even admit that Russia was serious about developing new nuclear weapons or violating the INF treaty despite the urging of this Committee and others. Even with that admission, no action was taken despite the recommendations from the Chairman of the Joint Chiefs General Dempsey. That inaction has led to the situation we find ourselves in today," he said.