U.S. Secretary of State Condoleezza Rice Sunday called on North Korea to make transparent fully its nuclear weapons program amid reports it was secretly assisting Syria to develop an atomic weapons facilities, the AFP reported in New York.

"There are frankly a lot of questions that remain to be answered and we want to be able to answer questions about all aspects of the North Korean nuclear program," AFP quoted Rice as telling reporters with her Chinese counterpart Yang Jiechi beside her, before their talks on the sidelines of the U.N. General Assembly.

"So that"s very important," she was quoted as saying as preparations got underway for a crucial round of talks among the United State, China, Russia, Japan and the two Koreas beginning Thursday in Beijing aimed at ending Pyongyang"s nuclear weapons program.

The chief US diplomat and Yang discussed issues linked to the six-party talks, a State Department official said.

Rice did not cite the reported North Korean-Syrian links. If true, they could cast a dark cloud over U.S. policy towards North Korea, which U.S. President George W. Bush, weighed down by the unpopular war in Iraq, has hailed as a success.

U.S. and British newspapers have reported that North Korea was secretly helping Syria to develop a nuclear weapons facility.