Poor weather conditions in South Siberia's Altai Republic may prevent the search for the crash site of a Progress-M spacecraft for the second consecutive day, a Russian space official said on Friday.

The debris of the Progress M-12M space freighter presumably fell in the Altai mountains after the spacecraft failed to separate from the Soyuz-U carrier rocket in an abortive launch on August 24.

"Unfortunately, we don't have weather again this morning," said Alexander Dvurechensky, deputy head of a department in the Russian Federal Space Agency responsible for the search of fallen space debris.

A week of search has not brought any success so far, although the specialists believe they have covered about 90% of the territory where the pieces of the spacecraft may have fallen.

The main goal of the search is to determine whether the crash site has been contaminated with heptyl, a highly toxic rocket propellant which the Progress carried for the International Space Station.

The absence of the debris may confirm the theory that the spacecraft could have completely burned up in the Earth's atmosphere.