TEHRAN - Iran will not suspend its disputed nuclear program even if the United States imposes sanctions targeting companies that ship fuel to the Islamic Republic, a Foreign Ministry spokesman said Monday.

Twenty-five U.S. senators from both parties have proposed giving President Barack Obama new leverage in the dispute over Tehran's nuclear ambitions. The bill gives Obama the authority to sanction companies supplying petrol to Iran.

The United States and its Western allies suspect Iran is aiming to develop nuclear bombs under the cover of a civilian program and want it to halt sensitive uranium enrichment. Iran rejects the allegation and says it will not bow to pressure.

We can cope with such measures (U.S. sanctions). Sanctions and threats will not stop Iran from continuing its nuclear work, Foreign Ministry spokesman Hassan Qashqavi told a weekly news conference.

Iran is the world's fourth-largest oil exporter but lacks refining capacity to meet domestic demand and so relies heavily on international imports to guarantee fuel at the pumps.

Washington has threatened crippling sanctions against Iran if it did not end its sensitive nuclear activities.

During his 2008 presidential campaign Obama expressed interest in using Iran's dependence on imports of refined petroleum products as leverage in the nuclear standoff. But U.S. lawmakers say that under current law his powers to do so are limited.

Under the bill, a foreign oil company found to be in violation would be prevented from owning retail petrol stations in the United States or delivering crude oil to the U.S. Strategic Petroleum Reserve.

Similar legislation has been introduced in the House of Representatives and the Senate.

Though Iran holds some of the world's biggest crude oil reserves, it imports 40 percent of its gasoline to meet growing domestic demand. Expensive government subsidies help keep gasoline in Iran much cheaper than elsewhere.

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