Nevada Gov. Brian Sandoval announced Tuesday that he will not run for the U.S. Senate seat being vacated by longtime Democratic Sen. Harry Reid.

The announcement ends speculation that the popular Republican would enter the race and clears the way for another top-tier GOP candidate to join with his blessing. Sandoval, who sailed to re-election in November with 71 percent of the vote, was widely considered a favorite if he chose to run.

"My heart is in my responsibilities as governor and continuing to build the New Nevada," he said in a statement. "My undivided attention must be devoted to being the best governor, husband and father I can be."

Former Nevada Attorney General Catherine Cortez Masto, a Democrat, announced in April that she would seek the post, while a potential primary foe, U.S. Rep. Dina Titus, said she would not join the race and instead seek re-election to the House.

On the Republican side, three-term Republican U.S. Rep. Joe Heck has said he is exploring a bid. Republican Las Vegas City Councilman Bob Beers has long said he is in the race, although he's considered a long shot for the seat.

Reid, 75, the Senate Democratic leader, announced in March that he would not seek a sixth term. The decision came after an exercise injury that left him blind in one eye.

Sandoval, 51, had been batting away questions about his political future for the past four months while he successfully ushered a $1.1 billion tax plan and bills authorizing major education investments through the Republican-controlled Nevada Legislature.

"I sincerely thank Sen. Dean Heller and the many people who encouraged me to run and graciously afforded me and my family the time to arrive at this decision," he said Tuesday. "I look forward to supporting the ultimate Republican nominee."