A fuel leak in the rocket engine forced India to abort the launch of its landmark moon mission less than one hour before liftoff, media reports said Tuesday.

A committee of experts was looking into the causes of the problem that put back the bid to become just the fourth nation - after Russia, the United States and China - to land a spacecraft on the moon.

Having halted the countdown 56 minutes and 24 seconds before the scheduled launch of Chandrayaan-2 - or Moon Chariot 2 - the Indian Space Research Organization gave no explanation for what it called a "technical snag" in the rocket nor a date for a new attempt.

"As a measure of abundant precaution Chandrayaan-2 launch has been called off," ISRO said.

However, the Times of India quoted a senior mission scientist as saying there had been a leak in the GSLV-Mk III rocket's helium fuel component.

"After filling helium, we found the pressure was dropping, indicating there was a leak," the unnamed scientist said, adding that it was possible there were "multiple leaks."

"We were lucky that the mission did not enter the automatic launch sequence else all would have been lost," the Hindustan Times quoted a senior ISRO official as saying.

The report added that scientists were "racing to plug the leak" in time for a new launch window at the end of July.

Experts said Indian mission chiefs would be cautious about trying a new liftoff.

"If the launch does not happen in the next 48 hours, it could be postponed for a few months until we get an opportune launch window," said Ravi Gupta, a scientist formerly with the state-run Defense Research and Development Organization.

India has spent about $140 million on Chandrayaan-2, with most of it home-made. It is one of the cheapest in the crowded space race.

The launch would have been the third to the moon this year.

China put its Chang'e-4 mission on the lunar surface in January, while Israel's $100 million Beresheet crash-landed when it sought to become the first privately funded mission in April.