The United States is racing to develop hypersonic missiles that can travel at five times the speed of sound, officials have confirmed.

Heather Wilson, secretary of the US Air Force, said the effort was being made to keep pace with other nations like Russia and China while speaking on Friday at the Centre for Strategic and International Studies, a Washington think tank.

The US Air Force currently operates 80 satellites in space, the secretary added. Her comments followed reports suggesting Russia was also developing new missile systems after Washington announced plans to exit from a landmark nuclear arms control pact.

Vladimir Putin said over the weekend that Russia has suspended the Cold War-era Intermediate-range Nuclear Forces Treaty (INF) which banned both countries from stationing short and intermediate-range land-based missiles in Europe.

Meanwhile, Moscow and Washington have accused each other of violating the treaty and Mr Putin said Russia had acted after the United States announced it was withdrawing from the pact.

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Washington had made clear it planned to start research, development and design work on new missile systems and Moscow would do the same, Mr Putin said.

He added the Russian military should start work on creating land-based launch systems for an existing ship-launched cruise missile, the Kalibr, and for longer-range hypersonic missiles.

Russian officials have said the work should be completed by the end of next year so the new systems were ready by 2021.

Still, US disarmament ambassador Robert Wood told a UN-sponsored Conference on Disarmament in Geneva on Tuesday that the country would reconsider its withdrawal from the INF treaty “should Russia return to full and verifiable compliance”.

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“This is Russia’s final opportunity to return to compliance,” Mr Wood said.