"The project is very interesting and I am not turning it down," Interfax quoted space agency chief Anatoly Perminov as saying in Berlin, apparently referring to a plan announced last month to send a six-man crew to Mars.

"Any project is flatly rejected by some and fully supported by others at first. We hold a fairly progressive, professional, neutral stance. We support it, and it should be further developed," he said.

Georgy Uspensky, a researcher at the Central Research Institute for Machine-Building, Russia's premier authority on space equipment design, said in April that it would carry out the project with funding promised by Aerospace Systems, a little-known private Russian company that says it draws no resources from the state budget.

Uspensky said the small US$3-5 billion budget for the mission reflected plans to use already developed spacecraft, and predicted it would happen around 2011-2013.

A spokesman for the Russia's Federal Space Agency said at the time that he had never heard of the project and that it would be impossible to implement with such a meager budget and in such a short time period.

Perminov, who took over as space agency chief in a government reshuffle in March, said the project should be international.

"It would be very difficult for one country to carry out such a program," Interfax quoted him as saying. He said a mission to Mars would require adequate funding.

Perminov said the Russian agency has discussed manned Moon and Mars projects with NASA, the U.S. space agency.

Earlier this year, U.S. President George W. Bush proposed a manned mission to Mars but did not set a timeline for such a trip, which American scientists believe would probably remain decades away.