The risk of loose debris crashing into the International Space Station (ISS) forced three astronauts to seek emergency shelter.

An American and two Russians aboard the station have moved into the Soyuz vehicle, which is currently docked to the orbiting station, as a precaution to escape from the debris.

Nasa said on its website that the ISS crew resumed operations following an all-clear from mission control.

"They will reconfigure the station for normal operations and then continue their research work during the day."

The organisation said: "All station systems are operating normally and the crew will move out of the Soyuz spacecraft in which they stayed during the debris pass.

"They will reconfigure the station for normal operations and then continue their research work during the day."

Three new Expedition 44 crew members are preparing to head to the station aboard the Soyuz TMA-17M spacecraft on 22 July.

The latest incident is the fourth since the ISS began operations, forcing the crew to move to the Soyuz for protection from potentially dangerous debris.

Nasa astronaut Scott Kelly was quoted by Associated Press as saying: "Happy there was no impact.

"Great coordination with international ground teams. Excellent training."

The US Defense Department currently monitors around 22,000 forms of orbital debris.

There could be more than 500,000 1cm-sized objects in space that pose significant risks to orbiting craft such as the space station.