BOSTON (AP) - Boston Mayor Thomas Menino is lending his political clout to fellow Democrat Edward Markey in the state's special U.S. Senate election.

Menino endorsed Markey on Friday during an event at a Boston union hall.

Among other things, the mayor credited Markey for being out front on gun control and for securing federal funding for medical research institutions, a key part of the city's economy.

Markey said he was honored by the endorsement.

The Democrat, who was first elected to the House in 1976, has been criticized by Republican nominee Gabriel Gomez for being in office too long. But Menino, the city's longest-serving mayor, said longevity should be considered a good thing.

Menino wields a potent political organization in Boston that could help Markey's get-out-the-vote effort in the June 25 election.