PROVIDENCE — Saying that his work in the capital city is not finished, Mayor David N. Cicilline announced yesterday that he will seek reelection in 2010, ending persistent speculation that the Democratic mayor and former state legislator would seek the governor’s office, and opening speculation on who might challenge the two-term incumbent.

“We face the most serious economic crisis our state and our country has ever faced since the Great Depression. Continuing our work is the key to putting Providence in the strongest position possible when the recession ends,” said Cicilline, who opted to forgo the traditional news conference and instead released a four-minute video on YouTube yesterday afternoon.

The announcement further pares the field of high-profile potential candidates to succeed Republican Governor Carcieri. Cicilline, 47, was the first openly gay U.S. mayor when he took office in 2003. The nation has yet to see an openly gay governor.

Democrat Frank Caprio, the state general treasurer, remains the man to beat, with a war chest topping $1 million and leading all candidates in recent polls.

Attorney General Patrick C. Lynch and Lt. Governor Elizabeth H. Roberts also are seen as viable Democratic candidates.

On the Republican side, former Cranston Mayor Steven P. Laffey, who lost a 2006 primary bid for the U.S. Senate seat now held by Democrat Sheldon Whitehouse, ended speculation about his plans when he said last week that he will not run for governor.

State Rep. Joseph A. Trillo, R-Warwick, has said he is weighing a run. So has former U.S. Sen. Lincoln D. Chafee, now a political independent, who deflected Laffey’s challenge in the 2006 primary.

Cicilline said in an interview in City Hall yesterday that he had to weigh his political aspirations for the highest office in the state against the prospect of a third term as mayor of Rhode Island’s largest city. Cicilline has also been mentioned as a possible Congressional candidate.

Recent polls have shown that Cicilline’s popularity statewide has diminished, in large part due to his administration’s handling of a tax scandal involving his brother, the now-disbarred lawyer John Cicilline, who is serving time in federal prison on unrelated charges.

At best, Cicilline is the third most popular Democrat in the state, behind Caprio and Lynch, according to polls. But the mayor insisted those numbers did not factor into his decision.

“Any time you consider an elected office, you choose the position that’s a good fit,” Cicilline said. “This makes the most sense to me. This is the best job I’ve ever had.”

Marion Orr, director of the A. Alfred Taubman Center for Public Policy at Brown University, said he was not surprised that Cicilline opted not to run for governor.

“With the exception of a few, mayors of big urban cities have a difficult time moving up the political ladder,” Orr said. “The demographics of a city tend to be different from the broader statewide electorate, which means that an urban mayor will often take positions that are popular with the city base, but not necessarily the state base.”

Cicilline said he chose to announce his reelection plan yesterday only because his mind was made up and he was approaching a spring deadline he had set for himself . (Yesterday was also the day that the governor released his budget proposal for next year.)

“I’ve found that there’s nothing gained from waiting, so once I made up my mind, I wanted to let people know,” he said.

The son of a Jewish mother and Italian-American father, Cicilline was elected to the House of Representatives in 1995, representing the city’s East Side for four terms. Cicilline came out as a gay man during his time in the General Assembly.

Cicilline captured the mayor’s seat in 2002, sweeping a four-way primary on his way to winning the November general election. He succeeded John Lombardi, then-City Council president, who briefly served after Mayor Vincent A. Cianci Jr. resigned as a result of his conviction on federal racketeering charges. Cicilline faced down a Democratic primary challenger and a Republican challenger during his 2006 bid for reelection.

Providence is being battered in the national recession that does not appear to have hit bottom.

The booming economic development and building investment that earned it the moniker Renaissance City early in the decade is now under siege by the very things that crippled the nation’s economy: the decline in home values, the rising rates of foreclosed homes, unemployment and business closings.

Orr, of the Taubman Center, said Cicilline’s potential reelection might benefit a city facing challenging times: “A level of stability in that office might be helpful.”

Cicilline says the city must protect the gains and progress made in rebuilding neighborhoods, improving the public school system, reducing crime and encouraging economic development and job growth.

The risk that the city can slide back into disinvestment and blight if the wrong decisions are made is what Cicilline says compels him to seek reelection: “We can’t go backward. We’ve gone too far in moving our city forward.”