Thousands of Iranians nationwide demonstrated Sunday to celebrate the 28th anniversary of the takeover of the US Embassy by militant students, state television reported. Demonstrators in the capital, Teheran, including elementary school students, gathered outside the former US Embassy, chanting anti-US and anti-Israeli slogans. They burned the two countries' flags and warned Washington to learn from the hostile incident. The takeover, which occurred during Iran's 1979 Islamic revolution, severely damaged relations between the two countries. The 52 Americans who were held hostage during the crisis were returned after 444 days, but the US cut off diplomatic ties with Iran to protest the incident. State television showed video footage of the takeover Sunday and images of the Americans who had been held hostage. Current relations between the two countries continue to be incredibly tense, with the US accusing Iran of covertly developing nuclear weapons and supporting Shiite militias in Iraq - charges Tehran denies. "The US has designed a triangle of military, cultural and economic threats against the Iranian nation," Mostafa Pourmohammadi, Iran's interior minister, said during Sunday's demonstration, which happens every year on Nov. 4. The Iranian official dismissed a new set of unilateral sanctions against Iran that Washington announced recently. "The Americans threaten once and give in ten times because they know that the Iranian nation is greater and more stable than the threats," said Pourmohammadi. The US is pushing for a new round of UN Security Council sanctions to force Iran to suspend uranium enrichment, which can produce fuel for a nuclear reactor or fissile material for a bomb. Two previous sets of UN sanctions have failed to persuade Iran to alter its behavior.