HARRISBURG, Pa. (AP) — Republican U.S. Rep. Lou Barletta of Pennsylvania, who was elected as a crusader against illegal immigration and helped cheerlead Donald Trump to victory last year, has told GOP officials and activists that he has decided to run for the U.S. Senate seat now held by Democrat Bob Casey.

A person familiar with the discussions told The Associated Press that Barletta began telling party officials of his decision last week, several months after he began considering it. The person spoke on condition of anonymity Monday because Barletta has not yet made his plans public.

In a text message Monday, Barletta said that his conversations have been "very positive" and that he will announce his decision in a few weeks.

"Continuing to go through process. Been talking to a lot of people," Barletta wrote.

Barletta, 61, is in his fourth term representing a House district that stretches from south-central Pennsylvania's rolling farms through northeastern Pennsylvania's anthracite coal fields.

Barletta, a staunch Trump supporter in Congress, would quickly become the most recognizable name in a field of a half-dozen would-be challengers to Casey, the 57-year-old son of a late ex-governor and a fierce critic of the Republican president.

Barletta has supported Trump-backed legislation to overhaul the American health care system and introduced a bill to fund the construction of a wall along the U.S.-Mexico border to help Trump fulfill a key campaign promise.

Barletta won his House seat during the Republican midterm wave of 2010, catapulted by the attention he received while mayor of the small city of Hazleton for cracking down on immigrants in the country illegally.

Hazleton approved Barletta's measures in 2006, denying permits to businesses that hire people in the country illegally and fining landlords who rent to them, but they were never enforced before the U.S. Supreme Court struck them down in 2014. Barletta's strategy was copied by dozens of other cities across the U.S. that accused the federal government of failing to enforce immigration laws.

Barletta endorsed Trump in the weeks leading up to Pennsylvania's presidential primary last year. He became a co-chairman of Trump's ultimately successful campaign in the state and served on Trump's transition team.

Casey plans to seek a third six-year term in next year's election. Democrats' 4-3 ratio registration edge over Republicans gives him a built-in advantage, though that did not stop Trump from becoming the first Republican since 1988 to capture Pennsylvania's crucial electoral votes in the presidential race.

Casey — perhaps the closest thing to a political household name in the nation's sixth-most populous state — will be one of 10 Democrats nationwide defending a seat next year in a state won by Trump.

Casey reported $5.6 million in his campaign account as of June 30, the latest date for which Senate candidates must disclose campaign finances. That was almost twice the amount of money that Casey had at the same point when running for his current term. Barletta reported just over $500,000 in his account, although he also reported a nearly $100,000 debt.

Also running are Jeffrey Bartos, a Republican and real estate investor from suburban Philadelphia; Paul Addis, a Republican and former energy-sector executive also from suburban Philadelphia; and several other candidates, including two state representatives from western Pennsylvania.

Pennsylvania's Republican U.S. Sen. Pat Toomey spent $27 million in the two-year campaign cycle to win re-election last year.

___

Associated Press writers Alan Fram and Erica Werner in Washington contributed to this report.