India on Monday called off the launch of a rocket aiming to take a probe to the Moon less than one hour before blast-off because of a "technical" problem.
India had hoped that the Chandrayaan-2 - or Moon Chariot 2 - mission would make it only the fourth country after Russia, the United States and China to land a craft on the lunar surface.
The countdown to launch at the Satish Dhawan Space Centre was halted 56 minutes and 24 seconds before the planned liftoff at 2:51 am (2121 GMT Sunday).
"A technical snag was observed in launch vehicle system at T-56 minute," the India Space Research Organisation said on Twitter.
"As a measure of abundant precaution, #Chandrayaan2 launch has been called off for today. Revised launch date will be announced later."
Media at the space centre on an island off the coast of Andhra Pradesh state were told the launch would not take place Monday.
Officials did not give details of the problem or say when a new launch could be held.