China cautioned today against taking the issue of Iran`s nuclear program to the United Nations Security Council, saying that doing so might lead the Iranian government to end all cooperation with the UN`s nuclear watchdog agency. ``Referring it to the Security Council might complicate the issue,`` Wang Guangya, China`s ambassador to the UN told reporters in New York. ``That might make some of the parties more tough on this issue. That is our concern.`` Guyangya wouldn`t say whether China would vote against referral to the Security Council when that question comes before the board of governors of the International Atomic Energy Agency in Vienna. The U.S. and its European Union allies said yesterday that the Iranians` Jan. 10 decision to resume research on the nuclear fuel cycle showed that talks to persuade Iran to abandon its nuclear program had failed. Germany, France and Britain, the so- called EU-3, urged the IAEA to hold an emergency meeting to vote on referring Iran to the Security Council, where Iran might face censure or sanctions. China`s position is critical to any action because of its veto in the Security Council and previous opposition, along with Russia, to referring the issue to the 15-mamber panel. U.S. Secretary of State Condoleezza Rice is focusing her diplomatic efforts on China and Russia, which also wields a veto in the council. She spoke earlier this week with Russian Foreign Minister Sergey Lavrov and said she would speak soon to her Chinese counterpart as well. China, the third-biggest buyer of Iranian oil, and Russia, which has sold anti-aircraft missile systems to Iran and is helping the country build a nuclear reactor, have so far led opposition to demands for a referral.