Albuquerque Mayor Martin Chavez announced Tuesday he will seek the Senate seat of retiring GOP Sen. Pete V. Domenici, becoming the first high-profile Democrat to enter the race.

Chavez joins Rep. Heather A. Wilson, R-N.M., in what is expected to be one of next year’s most competitive and expensive congressional races.

Domenici announced last week that he is retiring for health reasons.

Chavez rose quickly on the short list of potential Democratic contenders after two major figures who would have been strong candidates said last week they would not run. New Mexico Gov. Bill Richardson said he intended to continue his campaign for the 2008 Democratic presidential nomination, while Rep. Tom Udall of the northern 3rd District said he could better serve his state from his seat on the House Appropriations Committee.

Democrat Don Wiviott, a wealthy Santa Fe developer, already had filed to challenge Domenici and has expressed willingness to tap his personal resources for his campaign, though he is not well known in state party circles.