It looks increasingly like Democrats are going to have a dogfight on their hands in suburban Philadelphia's 6th Congressional District.

Rep. Chris Carney (D., Pa.) announced today that he is endorsing Manan Trivedi, a Reading doctor and veteran of the Iraq war, in the primary – the first member of the state's congressional delegation to back Trivedi.

"Through his work as a physician, health reform advocate and military officer, Manan Trivedi has shown an admirable dedication to service," Carney said in a statement. "He has the real-life experience to help fix our country's health care system and . . . his experience serving on the front lines in the Iraq war gives him invaluable perspective on issues of foreign policy and national security."

Former Inquirer editorial writer Doug Pike declared his candidacy in April, hoping to sew up the nomination early on the strength of his personal wealth and a pile of endorsements from prominent Democrats and local labor unions. After Trivedi entered the race in September the two have engaged in hand-to-hand combat for endorsements and cash.

The idea: demonstrate viability to the Democratic Congressional Campaign Committee and national party leaders and donors. The 6th District seat will be open in 2010 because incumbent Rep. Jim Gerlach (R.,Pa.) is leaving to run for governor; both parties are targeting the race.

Today the Pike campaign rolled out a nod from Rep. Nikki Tsongas, Democrat of Massachusetts, as its latest entry in the endorsement arms-race.

In the congressional delegation, Pike boasts the support of Democratic Reps. Bob Brady, Chaka Fattah, Allyson Schwartz and Patrick Murphy. Pike is the son of a congressman, Rep. Otis Pike of New York, who chaired the House Select Committee on Intelligence in the 1970s.

Carney, elected in 2006, represents the 10th District in Northeast Pennsylvania. He was recently promoted to commander in the U.S. Navy reserve.

Trivedi is a former lieutenant commander in the Navy who served as a battalion surgeon with the Marines in Iraq.

In the past two weeks, his campaign has announced 40 endorsements from local elected officials in the district, which is in Mongtomery, Berks and part of Lehigh counties.

Among them was one defection - Fred Sheeler, the Berks County recorder of deeds, initially endorsed Pike, then withdrew his backing and announced his support of native son Trivedi. State Sen. Daylin Leach (D.,Montgomery) earlier had taken back his Pike endorsement and declared himself neutral.

During the same time period, Pike announced that he had landed two major Pennsylvania fundraisers on his team: Richard Schiffrin, national finance co-chair for Hillary Clinton's presidential campaign last year and lobbyist Bill Titelman.

Pike had raised $902,000 through Sept. 30, according to Federal Election Commission filings; of that $620,000 was his own money.

Trivedi raised $127,000 in just three weeks in September, of which $13,000 was a self-donation.

Contact staff writer Thomas Fitzgerald at 215-854-2718 or tfitzgerald@phillynews.com.