Updated: With quotes from Garagioa and O'Malley.
The state's top Democrat will weigh into one of the most competitive primary election in Maryland on Thursday.
Gov.Martin O'Malleywill back state Sen. Rob Garagiola in his bid to capture the nomination in the 6th Congressional District, a significant get for a candidate who has faced a stronger than expected challenge from Potomac banker John Delaney late in the campaign.
The endorsement comes nearly four months after Garagiola received the backing of Lt. Gov. Anthony Brown and it arrives at a potentially critical time for his campaign. Delaney recently reported out raising Garagiola by three-to-one this year. The primary is April 3.
"In the State Senate, Rob has been a leader in creating green jobs and developing a renewable energy industry in Maryland," O'Malley said in a statement released by the campaign. "He's been a courageous leader in our efforts to expand healthcare coverage to more Maryland families and to build Maryland's No. 1 ranked schools, and he was one of the key figures in helping pass marriage equality in Maryland. He has never shied away from casting the difficult and tough votes necessary to move our state forward."
Garagiola has long enjoyed the support of the state's powerful labor groups -- which can help drive voter turnout by encouraging members to vote -- as well as other top Democrats in the state, such as Southern Maryland Rep. Steny Hoyer. Delaney has been endorsed by Comptroller Peter Franchot, Rep. Donna Edwards and former President Bill Clinton.
The district, which includes Western Maryland and portions of Frederick and Montgomery counties, was heavily redrawn by Democrats in Annapolis last year -- including O'Malley -- to be more competitive. Republican Rep.Roscoe G. Bartlett has represented the district for 10 terms and is seeking reelection.
It was not clear if O'Malley and Garagiola were planning to hold an event to announce the endorsement Thursday.
O'Malley and Garagiola will hold an event in Annapolis at 4:30 p.m.