The pledge by Ali Larijani, head of Iran's national security council, contradicted an Iranian government statement earlier in the week that said it was keeping open the option of quitting the treaty.

"Iran will still honor the principles of the nuclear Non-Proliferation Treaty and continue to seek a just and reasonable solution to the Iranian nuclear issue through talks," Larijani said, according to China's Xinhua news agency.

He made the remark Thursday while meeting with Chinese State Councilor Tang Jiaxuan, one of China's top diplomats.

Larijani is in China for a two-day stop that includes a meeting later Friday with President Hu Jintao.

China, which has major energy interests in Iran, supports Tehran's right to a nuclear energy program.

China last month voted in favor of a United Nations resolution that imposes sanctions on Iran over its nuclear program, but Beijing sought to water down the measure and has said it prefers negotiations instead of sanctions.

The sanctions take aim at Iranian efforts to enrich uranium, which the United States and others fear could be used to make a nuclear weapon.

On Thursday, State Councilor Tang reiterated the call for negotiations in his meeting with Larijani.

"Under the current circumstances, it has become more necessary and pressing to resume the negotiations," Tang said, urging all sides to "show flexibility".

On Tuesday, Iran said it could drop out of the non-proliferation treaty if Western pressure increased over the nuclear issue.

"If we are put under pressure and deprived of our rights, we can use our capacity to decide whether to stay within the treaty or to quit it," government spokesman Gholam Hossein Elham told reporters.

Larijani will deliver a message from President Mahmoud Ahmadinejad to Hu during his visit, Iranian state media have said. Few other details have been given.

"Larijani will meet with Chinese leaders... to exchange opinions on bilateral issues, Iran's nuclear issues, and other regional and international topics of common concern," China's foreign ministry spokesman Liu Jianchao told a regular press conference on Thursday.

China, increasingly looking abroad to meet its growing energy needs, has aggressively pursued oil and gas deals in Iran.

Last month China's top energy firm, PetroChina, struck a mammoth deal worth 16 billion dollars for the purchase of Iranian liquefied natural gas.

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