Moscow, Aug 25 (IANS/RIA Novosti): Russia may fail to fulfill its obligations in delivering crews to the International Space Station after Wednesday's accident with Russia's Progress M-12M space freighter, a source in Russia's space industry said.

The space freighter fell in South Siberia's Altai Republic Wednesday after failing to separate from the Soyuz-U carrier rocket, the first loss of the Progress freighter in the history of Russia's space industry.

A rocket engine failure is believed to have caused the accident.

"The scheduled launches of the [Soyuz] rockets are likely to be suspended because of the space freighter accident... until the reasons [of the accident] are established," the source said.

This means that members of the International Space Station (ISS)'s crew are likely to stay at the station longer than planned and that the new crew will not be able to replace them on schedule, he said.

After the retirement of the US shuttle fleet earlier this summer, Russian Soyuz craft became the only way for astronauts to reach the ISS until at least the middle of the decade.

The Soyuz-U carrier rocket blasted off from the Baikonur Space Centre in Kazakhstan and was scheduled to separate at 5.09 p.m. Moscow time.

The source said the engine failure made it impossible for the spacecraft to achieve the required orbital velocity.

The space freighter was to deliver 2.7 tonnes of food, medical and scientific equipment, and other items to the ISS, the source said.

Russian space agency Roscosmos promised that the failure to deliver food to the ISS would not affect its crew, saying that food stocks on board the ISS were enough to sustain the crew for a "long time."

Wednesday's accident is the second spacecraft loss for the Russian space industry in within a week.