MOSCOW - Russia's space agency has revised its forecast of the course of the failed Mars probe Phobos-Grunt, saying it would now fall into the Pacific Ocean off Chile between Sunday and Monday.

According to Roscosmos, the fragments of the probe are likely to fall to Earth at about 21:51 Moscow time (1751 GMT) Sunday at a position of latitude 42 degrees south and longitude 80 degrees west.

Specialists were constantly monitoring the Phobos-Grunt descent, Roscosmos said.

Earlier, experts said the 14-ton spacecraft carrying 11 tons of toxic rocket fuel might land somewhere in the southern Atlantic.

Most of the debris was expected to burn up in the atmosphere, but 20 to 30 chunks of charred debris, weighing about 200 kg, could make it to the surface, while the toxic fuel would burn in the atmosphere at a height of about 100 km, said Roscosmos. Just where it might crash would not be clear until hours before it actually happened.

Phobos-Grunt, Russia's most ambitious planetary mission in decades, was launched on November 9 with the aim of exploring one of Mar's two moons, but it became stuck in Earth orbit due to a propulsion failure and radio contact was lost.

International space agencies believe the chance of a person being hit by debris are tiny -- something like 1 in 20 trillion, based on the spacecraft's orbit and the amount of debris that might survive the re-entry.