Russia's space agency said on Saturday its ill-starred Mars probe would crash into the Pacific Ocean off the coast of Chile as the craft is expected to begin its final descent Sunday evening.

"The predicted window for the fragments of the Phobos-Grunt to fall to Earth is between January 15 and 16, with the central point on January 15 at 21:51 Moscow time (17:51 GMT)," the Roskosmos agency said in a statement.

It published an updated map showing the path of the gradually descending probe, predicting it would fall into the Pacific Ocean off the coast of Chile.

The space agency had several times changed its predictions due to factors like the altitude and atmospheric conditions, saying the probe could crash into the Indian Ocean and later estimating it could enter the atmosphere over Argentina and crash into the Atlantic Ocean.

In an embarrassing setback, the $165-million probe designed to travel to the Mars moon of Phobos and bring back soil samples, blasted off on November 9 but failed to leave the Earth's orbit.

The Russian space agency has said that 20 to 30 fragments weighing a total of no more than 200 kilogrammes were expected to fall to Earth, with the spacecraft's highly toxic fuel burning up on entering the Earth's atmosphere.