By John Collins
Updated: 12/29/2012 06:35:40 AM EST
LOWELL -- With Democratic support growing for U.S. Rep. Edward Markey's effort to claim U.S. Sen. John Kerry's Senate seat, U.S. Rep. Niki Tsongas said Friday she will not challenge Markey for the Democratic nomination.
Her announcement came on the same day Kerry, whom President Obama has nominated for secretary of state, and Victoria Kennedy, the widow of former Sen. Edward Kennedy, threw their backing behind Markey.
"I am gratified by the encouragement I have received to consider running for the Senate, but I believe that I can best advance the interests of my constituents in the Third Congressional District and the people of Massachusetts by continuing to serve in the U.S. House," Tsongas said in a prepared statement.
The statement was a change from one her spokesman released earlier in the day that did little to tamp down speculation that Tsongas would seek the seat and enter the Democratic primary.
"Ed's one of the most experienced and capable legislators in the entire Congress and it would be an almost unprecedented occasion for such an accomplished legislator to join the Senate able to hit the ground running on every issue of importance to Massachusetts," Kerry said in a prepared statement.