EU diplomats said on November 10 that Iran denies trying to build atom bombs. Iran Supreme Leader Ayatollah Ali Khamenei said any US or Israeli attack on its nuclear sites would be met with "iron fists.

The United States and Israel have refused to rule out any option to prevent Iran from acquiring a nuclear arsenal.

Diplomats in Brussels said preliminary discussions among EU capitals on new measures had begun and plans may be ready for EU foreign ministers in Brussels to approve on December 1.

Iran already faces a wide range of UN sanctions, as well as some imposed unilaterally by the United States and the EU.

New EU sanctions would be a significant part of Western efforts to ratchet up pressure on Tehran after the UN nuclear watchdog's report this week that laid bare a trove of intelligence suggesting Iran is seeking nuclear weapons.

Western governments would prefer further Security Council measures against Tehran. But Russia and China, both permanent Security Council members with veto power, are opposed and on November 10 said new sanctions would not work.