WASHINGTON (AP) -- A powerful pro-Israel lobby is backing a new political group that on Friday launched a multimillion-dollar campaign to oppose the nuclear pact the United States recently made with Iran.

The American Israel Public Affairs Committee is supporting an independent action committee called Citizens for a Nuclear Free Iran, dedicated to preventing Iran from obtaining the capacity to obtain nuclear weapons.

Spokesman Patrick Dorton said Friday that the group is launching a national TV and digital ad campaign in many media markets around the country.

"Democrats should be especially concerned because the deal increases the chances of war, will spur a nuclear arms race and rewards an Iran with a horrific human rights record," Dorton said.

The group's website lists an advisory board of five former Democratic and independent lawmakers - one-time Sens. Evan Bayh of Indiana, Mark Begich of Alaska, Mary Landrieu of Louisiana and Joe Lieberman of Connecticut along with former Rep. Shelley Berkley of Nevada.

On the other side of the issue, liberal groups, such as the Jewish Middle East lobby known as J Street, also are buying national ads to shore up congressional support for the deal.

Those for and against the agreement, which gives Tehran billions of dollars in sanctions relief in exchange for curbing its nuclear program, are lobbying lawmakers who have not yet decided whether or not to support the deal. A vote in Congress is expected after the August recess.

By The Associated Press