"The Soyuz capsule is returning to Earth via a ballistic descent, which is a sharper angle of landing compared to normal," said NASA mission control in Houston.
Rookie astronaut Nick Hague and veteran cosmonaut Aleksey Ovchinin "have been in contact with rescue forces," according to NASA.
Their spacecraft was expected to dock at the ISS within six hours after blastoff from Russia-leased Baikonur cosmodrome. Search and rescue teams have been deployed and are expected to arrive at the emergency landing destination within an hour and a half.
NASA said it is coordinating with Russia's space agency to determine the status of the operation.
More to follow…
ls/kms (Reuters, AP)