BEIJING — China balked Tuesday at the increased US sanctions against Iran last week over its nuclear program, criticizing the US for unilaterally expanding on UN sanctions. China said Tuesday that the United States and other countries should not expand on the latest UN sanctions imposed on Iran over its nuclear program.China did not exercise its veto power last month when the UN Security Council approved sanctions that target Iran's Revolutionary Guard, ballistic missiles and nuclear-related investments.The United States followed that up when President Barack Obama signed a bill Thursday that imposed tough unilateral sanctions against exports of gasoline and other refined petroleum products to Iran. It bans U.S. banks from doing business with foreign banks providing services to Iran's Revolutionary Guard."China supports the U.N. sanctions. China believes that countries should have correct implementation of the sanctions instead of expanding the sanctions," Foreign Ministry spokesman Qin Gang told a news conference.