Updated

A non-partisan interest group is calling on President Obama and American businesses to increase pressure on the Iranian regime to end its suspected pursuit of nuclear weapons.

United Against Nuclear Iran is launching a 30-second TV ad, called "Unclenched Fist," Tuesday on cable news networks.

The spot, which will run for two weeks, cites Obama's call in his inaugural address to Iran's rulers to "unclench your fist" but warns that country continues to be led by "radical rulers seeking nuclear weapons, threatening the world."

"Americans can do something about it. We can put economic pressure on the Iranian regime -- pressure to keep them from building a nuclear arsenal and ensure security for all of us," a narrator says.

The group, launched in September by Amb. Richard Holbrooke, State Department envoy Dennis Ross and former CIA Director James Woolsey, among others, is seeking to pull all the key levers of power to prevent Iran from building nuclear weapons. Holbrooke and Ross are no longer affiliated with the group since taking on roles in the administration.

A spokesman for United Against Nuclear Iran says the ad is part of an "ongoing conversation" and is not meant as an attack on the White House but rather a call for the U.S. government and the American people to closely monitor the Iranian response to Obama's overtures -- including his YouTube address to Iranians, his speech in Cairo last week and plans to invite Iranian diplomats to July 4 celebrations.

"President Obama is doing exactly as he promised and taking these small steps," said Joe Kildea, a group spokesman. "We now have to watch how Iran responds and keep the pressure up ... to ensure they stop the pursuit of nuclear weapons."