Former Speaker of the US House of Representatives Newt Gingrich (R-GA) (R) answers a questions as former Massachusetts Governor Mitt Romney listens at the first New Hampshire debate of the 2012 campaign in Manchester, New Hampshire June 13, 2011. [Photo/Agencies]

MANCHESTER, New Hampshire - Republican White House hopefuls criticized President Barack Obama's handling of the economy from the opening moments of their first major debate of the campaign season Monday night.

Former House Speaker Newt GIngrich was the first among seven contenders on stage to assail the president's economic policies, saying with 14 million unemployed Americans, "we need a new president to end the Obama Depression."

Rep. Michele Bachmann of Minnesota, invited as an unannounced contender for the 2012 nomination, used the occasion to announce she had filed papers earlier in the day to become a presidential candidate. The disclosure was in keeping with a feisty style she has employed since her election to Congress.

Obama was hundreds of miles (kilometers) away, vowing to continue his efforts to create jobs as the Republicans met on a stage at St. Anselm College in New Hampshire.

US Congresswoman Michele Bachmann (R-MN) speaks at the Americans for Prosperity Foundation's "Presidential Summit on Spending and Job Creation" in Manchester, New Hampshire April 29, 2011. [Photo/Agencies]