Tornadoes may delay Atlantis launch

Preparations are almost complete for the launch of the latest NASA mission, Atlantis, on Thursday. But officials say the take-off is threatened by the tornadoes hammering the southern States of the U.S.

A decision will not be made until closer to the launch.

The long-awaited mission is due to deliver a European science lab to the International Space Station.

It was initially postponed in December, when problems arose with the shuttle's emergency system.

European astronaut Leopold Eyharts has until later in March to set up the Columbus lab before the next shuttle arrives with his replacement.