JUNEAU, Alaska — Democratic former U.S. Sen. Mark Begich has refused to bow to calls from some fellow Democrats requesting that he end his run for Alaska governor, saying Tuesday that he's in the race to win.

"It's a three-way race, so get used to it," he said surrounded by family and supporters at his Anchorage campaign headquarters.

Begich was unopposed in winning the Democratic nomination and had insisted he wouldn't be running if he didn't think he could win. But he has faced pressure to quit.

Some Democrats and independents have worried that Begich and independent Gov. Bill Walker could split the vote and hand the race to Republican Mike Dunleavy, a former state senator. Walker was elected with Democratic support in 2014.

Tuesday marked the deadline for candidates to remove their names from the general election ballot. Begich's campaign had teased an afternoon announcement about the future of the campaign.

Begich said one of his opponents has support from the "Trump Republican party" and the other from "political bosses and the power structure, brokers." Walker was endorsed by the Alaska AFL-CIO.

Former Democratic party chairman Don Gray circulated a petition asking Begich to withdraw. Jay Parmley, executive director of the state Democratic party, has called the petition a stunt.

Gray said he'd like to see Begich run for U.S. Senate again or for governor, later. He called this a unique situation, motivated by a desire to see that Dunleavy is not elected.

Dunleavy's campaign said the so-called unity ticket of Walker and Democratic Lt. Gov. Byron Mallott was a "failed experiment" and that Begich, a former Anchorage mayor, is a career politician.

Walker said he is up to the challenge over the next two months of convincing Alaska voters that decisions made to address the state's budget deficit were right for Alaska.

Libertarian William "Billy" Toien also is running.

Alaska has had high-profile races with three major contenders before.

In 1990, Wally Hickel was elected governor as an Alaskan Independence Party candidate with about 39 percent of the vote, topping a field that included Democratic and Republican rivals. Hickel previously served as governor in the 1960s, as a Republican.

In 2010, U.S. Sen. Lisa Murkowski, who lost her Republican primary to upstart Joe Miller, ran a general election write-in campaign to keep her job, beating Miller. Democrat Scott McAdams was third.