CAPE CANAVERAL, June 12 -- A chartered spaceflight for India, Poland and Hungary's first astronauts in decades has been delayed indefinitely because of leak concerns at the International Space Station.

NASA said Thursday that it wants to monitor the cabin pressure on the Russian side of the orbiting lab before accepting visitors. Officials stressed that the seven astronauts currently at the space station are safe and that other operations up there aren't affected.

SpaceX was supposed to launch four private astronauts this week on a 14-day space station mission, but bad weather and SpaceX rocket trouble delayed the flight. Then the station leak issue cropped up.

The Russian Space Agency has been dealing with a cabin pressure leak at the...