FACTBOX: Sanctions against Iran

(Reuters) - Defense Secretary Robert Gates said on Friday he expected the international community to impose significant additional sanctions against Iran over its nuclear program.

Iran's pledges in Geneva talks last October won itself a reprieve from further sanctions but Western powers stressed they would not wait indefinitely for Tehran to follow through.

A senior U.S. official said the United States and its allies would decide early next year whether to pursue more sanctions.

Following are some details of the sanctions already imposed by the United States, European Union and United Nations:

* EXISTING U.N. SANCTIONS:

-- The Security Council has imposed three sets of sanctions on Iran, in December 2006, March 2007 and March 2008.

-- The first covered sensitive nuclear materials and froze the assets of Iranian individuals and companies linked with the nuclear program. It gave Iran 60 days to suspend uranium enrichment, a deadline Iran ignored.

-- The second included new arms and financial sanctions. It extended an asset freeze to 28 more groups, companies and individuals engaged in or supporting sensitive nuclear work or development of ballistic missiles, including the state-run Bank Sepah and firms controlled by the Revolutionary Guards.

-- The resolution invoked Chapter 7, Article 41 of the U.N. Charter, making most of its provisions mandatory but excluding military action. Iran again ignored an order to halt enrichment.

-- The third measure increased travel and financial curbs on individuals and companies and made some of them mandatory. It expanded a partial ban on trade in items with both civilian and military uses to cover sales of all such technology to Iran, and added 13 individuals and 12 companies to the list of those suspected of aiding Iran's nuclear and missile programs. In September 2008, the Security Council unanimously adopted a resolution again ordering Iran to halt enrichment, but imposed no more sanctions, due to opposition from Russia and China.

* EXISTING U.S. SANCTIONS:

-- Sanctions imposed after Iranian students stormed the U.S. embassy and took diplomats hostage in 1979 included a ban on most U.S.-Iran trade.

-- In 1995, President Bill Clinton issued executive orders preventing U.S. companies from investing in Iranian oil and gas and trading with Iran. Tehran has found other willing customers.

-- Also in 1995, Congress passed the Iran-Libya Sanctions Act requiring the U.S. government to impose sanctions on foreign firms investing more than $20 million a year in Iran's energy sector. It was extended for five years in September 2006. No foreign firms have been penalized. The U.S. terminated the applicability of the Iran-Libya Sanctions Act to Libya in 2004.

-- In October 2007 Washington imposed sanctions on Bank Melli, Bank Mellat and Bank Saderat and branded the Revolutionary Guards a proliferator of weapons of mass destruction. Two years later, in October 2009, the Treasury also sanctioned Bank Mellat in Malaysia and its chairman.

-- At the end of October, U.S. President Barack Obama signed into law legislation to punish foreign oil companies that export gasoline to Iran, marking the first time Congress has imposed economic sanctions on Iran to protest its nuclear program. The new law blocks the U.S. Energy Department from awarding contracts to companies to deliver crude oil to the U.S. Strategic Petroleum Reserve if they also sell or ship gasoline to Iran.

* EXISTING EU SANCTIONS:

-- The EU has imposed visa bans on senior officials such as Revolutionary Guards head Mohammad Ali Jafari, former Defense Minister Mostafa Mohammad Najjar and former atomic energy chief Gholamreza Aghazadeh, and on top nuclear and ballistic experts.

-- Britain said on June 18 that Iranian assets frozen in Britain under EU and U.N. sanctions totaled 976 million pounds ($1.59 billion).

-- Britain announced on October 12 that it was freezing business ties with Bank Mellat and Islamic Republic of Iran Shipping Lines, both of which have previously faced sanctions from the United States. Britain cited fears they were involved in helping Iran develop nuclear weapons.