Moscow (CNN) -- The Russian space agency on Monday postponed the launch of a new manned mission to the International Space Station due to last week's accident in which an unmanned cargo craft was lost, the state news agency RIA Novosti reported.
Alexei Krasnov of the space agency, Roscosmos, said the next manned mission, originally planned to launch on September 22, now would occur in late October or early November, according to the RIA Novosti report.
In the United States, NASA's space station program manager told reporters Monday that the timing of the rescheduled mission could force the temporary de-manning of the space station later this year.
However, the NASA official, Mike Suffredini, said no decisions can be made until a commission appointed by Russia completes its investigation of the August 24 crash involving a Soyuz rocket -- the same kind used to power the flights of crew members to the space station.
With a planned rotation of the six crew members aboard the space station scheduled to begin next month, a delay in using the Soyuz could prevent the ability to bring replacements, Suffredini said.
"If we don't have Soyuz flying by the middle of November -- the 16th or so, the normal landing time for the last crew -- we would have to de-man ISS at that point," Suffredini said.
The six astronauts at the space station are three from Russia, two from the United States and one from Japan.
Due to the schedule change announced Monday, the three Russian astronauts on board will return to Earth eight days later than originally planned, on September 16 instead of September 8, Krasnov said. They will fly a Soyuz vehicle already at the space station.
Suffredini said another Soyuz vehicle at the space station, which is set to fly back the other three crew members, will have its certification for the return mission expire by mid-November.
If there can't be a new manned mission from Earth by then, administrators will have to decide whether to take extensive steps to extend the vehicle's certification for the return flight, proceed on a return flight without certification, or de-man the space station by flying back the remaining crew members within the certification period, he said.
"We're going to do what's safest for the crew and for the space station," Suffredini said.
He acknowledged that leaving the space station without any crew members increased the risk for trouble.
"There is a greater risk of losing the ISS when it's unmanned than if it were manned," Suffredini said, adding that the risk increase "is not insignificant."
The commission in Russia investigating last week's accident will determine the new launch date for the next manned mission, Krasnov said, according to the RIA Novosti report. Prior to that mission, Roscosmos will make two unmanned Soyuz launches, "either an automated one or a freighter or both," he said.
On August 24, a Progress M-12M space freighter carrying food and other items to the space station broke up over southern Siberia after failing to separate from its Soyuz-U carrier rocket, RIA Novosti reported.
It was the first loss of a Progress freighter in more than 30 years of operation, according to the report, which said the cause was believed to be a rocket engine failure.
However, it was the second failed space launch in Russia in less than 10 days. On August 18, Russia lost a sophisticated Express-AM4 telecommunications satellite when the launch vehicle put it into the wrong orbit.
The Progress M-12M that went down last week was to deliver more than 3.8 tons of cargo to the space station crew, including food supplies, medical equipment, personal hygiene items and scientific equipment needed for experiments, according to Roscosmos and space officials.
Suffredini said Monday that space station crew is well-supplied due to the delivery of goods by the final U.S. shuttle mission carried out by Atlantis last month.
NASA is now reliant on the Russian space agency to ferry U.S. astronauts to orbit, since the grounding of the U.S. shuttle fleet has left the United States with no way to lift humans into space.
Plans are in the works for private companies to begin shipping cargo to the station, and eventually to carry astronauts as well.
CNN's Tom Cohen contributed to this report.