WASHINGTON -- As tensions between the U.S. and Iran continue to mount, an Iranian exile group viewed here as a terrorist organization is lobbying to play a greater role in the struggle against Tehran. And it is winning some support in Congress.

The Mujahedeen-e Khalq, or People's Mujahedeen of Iran, was formally listed as a terrorist group by the State Department because of its attacks on American military personnel and Iranian officials. It fiercely opposed the Shah and his supporters during the 1970s and allied with former Iraqi dictator Saddam Hussein in his 1980-88 war against Iran.

But today, the MEK and its supporters say the organization should be supported by the Bush administration as part of a broader effort to promote regime change in Tehran. They say the group has developed among the most-sophisticated intelligence operations covering Iran's leadership and nuclear operations, and it has networks inside Iran that can spread propaganda on democracy and on the need to remove the mullahs. The MEK also has 4,000 fighters that can target Iran from Iraq, though they have been demobilized by U.S. military commanders and held in a kind of house arrest.