The chief of Russia's space agency said the United States has rejected a proposal by Moscow to explore the moon jointly, a Russian news agency reported.

NASA announced in December it would establish an international base camp on one of the moon's poles, permanently staffing it by 2024. Officials with Russia's Federal Space Agency, Roscosmos, later said they had hoped to join NASA's program with Russian technology and experience.

NASA plans to have a four-person crew land in 2020 to start building a lunar base, shown here in an artist's rendering.
(NASA, John Frassanito and Associates/Associated Press)

But Roscosmos chief Anatoly Perminov was quoted by the Interfax news agency Sunday saying the United States rebuffed the offer.

"We are ready to co-operate but for some reasons the United States has announced that it will carry out the program itself," he was quoted saying.

"Strange as it is, the United States is short of experts to implement the program," Interfax quoted him saying.

There was no immediate comment by NASA to the report.

Perminov also said Russia had signed a $1-billion US contract with NASA for Russian cargo ships to deliver goods to the international space station over the next three years — an indication he said of the competitiveness of Russia's space services.

"If we had been uncompetitive, such contracts would not be signed," Perminov was quoted saying.

Russian spacecraft have been the workhorses of the international space station program, regularly shuttling cargo and people to the orbiting station — in particular after the U.S. space shuttle fleet was grounded following the Columbia disaster in 2003.

NASA will end the shuttle program in 2010 with plans to return to the moon in a new vehicle.