(CNN) Democratic Rep. Joe Kennedy III of Massachusetts has announced a run for Senate on Saturday morning at the East Boston Social Center, challenging Democratic Sen. Ed Markey, who has served in Congress for more than 40 years.

"We have a Senate that instead of trying to harness the opportunity and potential of every person in this country, they're trying to pull us back," Kennedy said Saturday in announcing his run. "And I'm running for the United States Senate to tear that down, to fight back with everything we've got."

In recent weeks, Kennedy, 38, has sought to draw a generational contrast with Markey, 73, while benefiting from the goodwill shown for the generations of Kennedys who have represented the state before him.

In a campaign email Saturday, Kennedy lists conversations he's had with constituents following President Donald Trump's election and "outdated structures and old rules" as reasons he decided to enter the Senate race.

"This is the fight of our lives, the fight of my generation — and I'm all in," he said.

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