National Aeronautical and Space Administration (NASA) Administrator Sean O'Keefe and China National Space Administration (CNSA) chief Sun Laiyan discussed their respective programs during the talks in Washington, NASA said.

NASA spokeswoman Debra Rahn said Sun was "very complimentary" of President George W. Bush's January 2004-unveiled goals for exploring the moon and Mars through international cooperation.

Bush had pledged that unlike the Apollo effort, which was a race with the Soviet Union, the United States would welcome international participation in a multi billion dollar plan to return Americans to the moon by 2020 and use the mission as a steppingstone for future manned trips to Mars and beyond.

The meeting between O'Keefe and Sun, planned for months, was sought by the Chinese side to initiate discussions with NASA on "areas of mutual interest," Rahn told AFP.

"But it needs to be clear that NASA is constrained in its ability to discuss new civil space cooperation until China addresses US proliferation concerns," she said.

Just Wednesday, the United States imposed sanctions on four Chinese entities, including a state-run firm, for selling weapons or cruise and ballistic missile technology and equipment to Iran.

The State Department vowed to step up its crackdown on dangerous weapons proliferators through "sustained and high-level engagement" with the Chinese government.

China's human rights record and concerns over proliferation of dangerous weapons and technology have limited NASA's offers of cooperation.

NASA cooperation with China at present is limited to "low level, project specific" fields in earth science under multilateral programs, Rahn said.

Officials say it is premature to speculate whether the Chinese will become a partner in any of NASA's space exploration goals.

The talks with Sun would be "an opportunity to exchange views - an opportunity to exchange thoughts" and "not a remarkable or unusual event," O'Keefe had said before the meeting.

But in mid-November, Chinese representatives for the first time joined a NASA workshop in Washington on international partnership and space exploration.

It was seen as precedent-setting by some space experts.

China launched its first astronaut, or "taikonaut," into space on October 15, 2003. The nation started a space program in 1970.

But it has been excluded from US-led partnership in the International Space Station confined currently to Canada, Japan, Russia, 11 nations of the European Space Agency and Brazil.

Rahn said Sun had extended an invitation to O'Keefe to visit China but no specific timetable for the proposed visit was discussed.

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