CONCORD, N.H. — Republican Scott Brown said Monday he will kick off his next campaign for U.S. Senate in Portsmouth, the New Hampshire city he says played a special role in his childhood.

The former Massachusetts senator will formally announce his bid for the seat held by Democrat Jeanne Shaheen at the Portsmouth Harborside Hotel on Thursday night.

“I remember our house on Islington Street, strolling through Strawbery Banke with my grandfather, and catching a show at Prescott Park. Now, Portsmouth is going to be the start of the next chapter in my life,” he told supporters in an email.

After months of speculation, Brown moved to his former vacation home in New Hampshire in December, created an exploratory committee last month and spent the last few weeks traveling around the state meeting voters. He said the top concern they have shared is a desire for a “health care system that works for New Hampshire – not one that leaves you with higher premiums, canceled policies and fewer medical options.”

Though at least two companies plan to participate next year, only one insurance company in New Hampshire currently is offering health plans under President Obama’s health care overhaul law, and it has faced criticism for creating a narrower network of hospitals for individual policyholders. About 22,000 people’s individual policies were canceled because they did not meet the law’s requirements, though the policyholders had the option to renew early and keep them temporarily.

Brown’s parents were stationed at New Hampshire’s Pease Air Force Base before he was born. He moved to Massachusetts as a toddler but often visited his grandparents on the New Hampshire seacoast growing up. Democrats have charged that he moved to Rye only to run for Senate.

In 2010, Brown won a special election in Massachusetts to replace Sen. Ted Kennedy, then lost his seat to Democrat Elizabeth Warren in 2012. In New Hampshire, Brown faces former U.S. Sen. Bob Smith, former state Sen. Jim Rubens and conservative activist Karen Testerman in the Republican primary.

Shaheen, a first-term senator and former three-term governor, has responded to Brown’s early campaigning by pressing him to sign a pledge like the one he signed in 2012 to reduce the outside money spent on the race.

“We hope, now that he is officially a candidate, Scott Brown will commit to the same standard he set in his last race on the other side of the border and tell the special interests to stay out,” Shaheen campaign manager Mike Vlacich said.

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