GOP front-runner Mitt Romney gained another high-profile endorsement on Thursday from National Republican Congressional Committee (NRCC) Chairman Pete Sessions (Texas), as party leaders continued to rally behind the former Massachusetts governor's candidacy.

The Romney campaign also announced the support of Sessions's fellow GOP Texas Reps. John Carter and Mac Thornberry.

Sessions, in a statement, called on Republicans to "unite behind the one candidate who can lead our party, win in November and put in place conservative pro-growth policies to restart our economy."

Carter praised Romney as a "proven job creator." "It is rare that leaders come along with such a tremendous record in the private and public sectors," he said.

Carter had endorsed Romney's 2008 bid for the presidency, but was a supporter of Texas Gov. Rick Perry's (R) 2012 campaign. Perry dropped out of the race after a poor showing in Iowa and ahead of the South Carolina primary. 

Thornberry said he trusted Romney to “not only defeat Barack ObamaBarack Hussein ObamaObama: Are we a nation that rips families apart? Another chance to seek the return of fiscal sanity to the halls of Congress Colombia’s new leader has a tough road ahead, and Obama holdovers aren't helping MORE, but implement pro-growth policies that will scale back the size of government and create jobs.”

The endorsements will provide a further boost to Romney ahead of the Texas primary in late May. Romney, the presumptive nominee, holds a greater than 2-to-1 advantage in delegates after Tuesday's trifecta sweep of nominating contests in Wisconsin, Maryland and Washington, D.C.

“These three men come from a long line of great conservative leaders from Texas and I am proud to have their support," Romney said in a statement released by the campaign.

“They share my goals for a smaller government, less debt and more jobs for our country. They have been hard at work fighting against the failed policies of the Obama administration. I look forward to working with them to defeat President Obama in November and putting conservative, pro-growth policies in place,” Romney added.

The three Texas endorsements come on the heels of former President George H.W. Bush’s endorsement of Romney in the Lone Star State last wek.

Rival Rick Santorum has indicated he will continue in the race and has banked his hopes for a comeback on victories in his home state of Pennsylvania and in Texas. Santorum communications director Hogan Gidley on Wednesday said a victory in Texas would be "vital" for the campaign.

A Rasmussen poll in mid-March placed Romney ahead of Santorum by 32 percent support to 30 percent in Texas.