AUGUSTA, Maine — Democratic Congresswoman Chellie Pingree announced Wednesday that she will not enter the U.S. Senate race and instead will focus on getting re-elected to a third term in the U.S. House.

Pingree’s decision comes just two days after independent Angus King, Maine’s governor from 1995-2003, declared that he would run for the seat that will soon be vacated by Olympia Snowe.

“This has been a very difficult decision and I will always be grateful for the tremendous support I’ve received from people all across Maine and around the country. I have been humbled by the enthusiastic encouragement I’ve gotten — from my neighbors here in Maine to my colleagues in Washington,” Pingree said in a statement Wednesday. “There is much at stake in this election and although the prospect of running for and possibly serving in the United States Senate was very exciting, in the end I concluded that I will best serve the people of Maine by running for re-election to the House.”

Since Snowe’s exit and Pingree’s initial announcement that she would gather signatures to enter the Senate race, a number of candidates have expressed interest in Pingree’s 1st District House seat.

It’s likely that most if not all of the Democrats who began gathering signatures last week will drop out with Pingree back in the mix. Among those are Pingree’s daughter Hannah Pingree, the former Maine House Speaker.

On the Republican side, only Patrick Calder had entered the race before Snowe’s announcement. Since, Maine Senate Majority Leader Jonathan Courtney has taken out papers to run in the 1st District.

Pingree likely has a strong chance of beating either of those candidates in the 1st District, which is much more liberal and Democratic than the 2nd. In 2010, she beat Republican Dean Scontras by a 57-43 vote at a time when Republicans won a majority in the Maine State House and the U.S. House.

With Pingree out of the Senate race, King now likely becomes the front-runner because he is poised to attract many Democratic voters.

“This is a personal relief to me because I wasn’t looking forward to running against a friend,” King said in a statement “I am pleased that Chellie will continue her work in Washington on behalf of the people of Maine as she is a dedicated and effective public servant.”

A poll conducted over the weekend by Public Policy Polling showed Pingree with the most support by far among Democratic candidates who have been mentioned as Senate candidates. Former two-term Gov. John Baldacci was a distant second, followed by former Secretary of State Matt Dunlap.

Dunlap, who has been in the Senate race since December, said Snowe’s decision turned him from “a primary front-runner to a footnote in about an hour.”

Pingree’s announcement could again elevate Dunlap, who said he aims to be the Democratic nominee.

“I’ve stayed in the Senate race the whole time. This was never about me just looking for a job,” Dunlap said Wednesday.

Baldacci has not made an official decision but people have been gathering signatures on his behalf.

State Sen. Cynthia Dill of Cape Elizabeth and Benjamin Pollard, a Portland homebuilder, also have been gathering signatures on the Democratic side.

Democrat Jon Hinck of Portland also said Wednesday night that he has decided to return to the Senate race after briefly considering running for Pingree’s seat in the House.

The Republican field in the U.S. Senate is still wide open and could be even after the filing deadline of March 15.

Among those in consideration are: Scott D’Amboise, who planned to run against Snowe in the primary, current Secretary of State Charlie Summers, who ran against Pingree in 2008, state Treasurer Bruce Poliquin, a 2010 gubernatorial candidate in 2010, Attorney General William Schneider, former state Senate President Rick Bennett and Assistant Senate Majority Leader Debra Plowman.

Most of the Republican candidates had little name recognition among the Mainers who were polled.

The PPP poll showed that King (36 percent) had the edge in a hypothetical three-way race against Pingree (31 percent) and Summers (28 percent), the leading GOP candidate.

In an interview with the Huffington Post on Wednesday, Pingree said she worried about her ability to win a three-way race with King and a Republican. She also said she talked to King several times over the last few days but could not persuade him not to run.