*Editor's note: This story has been updated throughout.

Texas GOP Chairman Tom Mechler announced his resignation Saturday, citing personal reasons. It's effective immediately, he said.

"Friends, this job is hard. The time commitment, financial commitment, stress and overwhelming responsibility takes its toll," Mechler said in his resignation letter. "After a lot of prayer and reflection, I’ve decided that it is time for me to focus on my family."

Mechler, an oil and gas consultant from Amarillo, also said he has experienced financial struggles over the past two years due to the downturn in oil prices. But it was the distance from his family — he estimated he has spent 80 percent of his time away from home — that ultimately led him to his decision, he wrote.

Speculation began swirling Wednesday that Mechler was preparing to step down, and party officials had said he would respond to the rumors Saturday. A number of potential candidates to finish Mechler's term had already started gauging support from the State Republican Executive Committee, which will make the choice in early June.

Mechler has served as chairman since 2015, when he took over after his predecessor, Steve Munisteri, went to work for the presidential campaign of U.S. Sen. Rand Paul of Kentucky. Mechler won re-election a year later, easily defeating challenger Jared Woodfill, the former chairman of the Harris County Republican Party.

Mechler's tenure has been prominently defined by the 2016 presidential election, during which he worked to get Texas Republicans on board with the controversial GOP nominee, Donald Trump. It was not an easy task — the state's junior U.S. senator, Ted Cruz, had waged a long, bitter battle against Trump throughout the primaries.

In his resignation letter, Mechler warned Texas Republicans against descending into warring factions, both after the presidential race and a still-unfolding legislative session. The party, he said, "needs to work harder than ever to come together."

"A party that is fractured by anger and backbiting is a party that will not succeed," Mechler wrote.

The SREC will pick Mechler's replacement at its next quarterly meeting, which is scheduled for June 2-3 in Austin. At least three potential candidates have surfaced: James Dickey, the chairman of the Travis County GOP; Rick Figueroa, a party activist from Brenham who is close to Mechler; and Mark Ramsey, an SREC member from Spring.

Shortly after Mechler announced his resignation, Figueroa told The Texas Tribune he is very likely to run. Figueroa, who unsuccessfully ran for Republican National Committeeman last year, is believed to be Mechler’s choice to take over.

Ramsey, the chief of staff to state Rep. Valoree Swanson of Spring, told the Tribune he is considering a campaign for chairman but has not decided yet.

Mechler did not endorse a successor in his resignation letter but encouraged the SREC to pick someone who will continue to work to grow the party.

"If we do not engage in the diverse communities across Texas, we will lose the state, then the nation, and there may be no coming back," Mechler wrote.

With Mechler's announcement imminent, the Texas Democratic Party issued a statement bidding him farewell, questioning whether he was departing because the state's Republicans are "more divided than ever," among other things.

"It's a damn shame Tom Mechler may be leaving the Texas Republican Party," Gilberto Hinojosa, the Democrats' chairman, said. "Personally, I always enjoyed our exchanges because he made Democrats look so good."