Russia would be willing to be a partner with the United States on a manned mission to Mars, a Russian space official said at the United Nations.

At U.N. headquarters to mark the International Day of Human Space Flight, Sergey Saveliev, deputy head of Russian space agency Roscosmos, said only international cooperation could make such a mission possible.

"I have to say that currently there is no country that could organize a manned spaceflight to Mars and a safe return," Saveliev said.

"We strongly believe that this project can be accomplished only through international cooperation," he said. "In this field, Russia is ready to cooperate with the United States, with Europe and with other countries."

NASA head Charles Bolden, attending the event, endorsed the idea of an international mission.

"We are absolutely trying to partner with everybody to go -- anyone who wants to participate," Bolden told SPACE.com. "Our goal is to try to form international coalitions.

"Almost everything we do today has some international flavor to it, whether it's science flights, or human spaceflights. I think you'll find everything we do from here on out is probably going to be international in nature."

While NASA has no timetable for sending humans to Mars, the agency says it is beginning work on a huge new heavy-lift rocket that could take a crew there and has set its sights on a first flight of the rocket, dubbed the Space Launch System, in 2017.