By Eric Bradner

CNN

WASHINGTON (CNN) -- Florida Rep. Ileana Ros-Lehtinen, a Republican who was the first Cuban-American elected to Congress, is retiring after 38 years -- handing Democrats a major opening to pick off a GOP-held seat.

The 64-year-old Ros-Lehtinen announced her decision to retire Sunday in an interview with the Miami Herald's Patricia Mazzei. She has been a key moderate voice in the House, but said her decision has nothing to do with her differences with President Donald Trump.

"I've served under all kinds of different dynamics in all these years that I've been in office here," she told the newspaper. "Though I don't agree with many, if not most, positions of President Trump."

Though Ros-Lehtinen was re-elected by 10 points in the fall, she represents a largely Democratic district. Hillary Clinton carried it by 20 points over Trump, and then-President Barack Obama bested Mitt Romney by 7 points there in 2012.

Ros-Lehtinen said the Democratic leanings of the district, which was redrawn prior to the 2016 election, had nothing to do with her decision.

"There is no doubt in my mind whatsoever that I would not only win in this election, but I would win by a greater percentage," Ros-Lehtinen said.

Democrats need 24 seats to retake control of the House. They hope to pick up one in a June special election in Georgia's 6th District, where Democrat Jon Ossoff faces Republican Karen Handel in the northern Atlanta suburbs.

Cole Leiter, a spokesman for the Democratic Congressional Campaign Committee, said Ros-Lehtinen's retirement all but guarantees a Democratic flip in 2018.

"It's been clear for years that the Republican Party was out of step with the values of Miami families, and Ileana Ros-Lehtinen's retirement announcement is testament to the fact she recognized how wide that gap had grown," he said. "As one of the most Democratic districts held by a Republican representative, this district was always going to be competitive. Now it is all but guaranteed to be won by a Democrat who will finally provide the hard working people who live there the representation they deserve.

After Ros-Lehtinen's announcement, Sen. Marco Rubio, also a Republican, tweeted that she would be missed, citing her advocacy for human rights and their friendship.

National Republican Congressional Committee Chairman Steve Stivers called the congresswoman "a force of nature" and expressed confidence about retaining her seat.

"Her tireless work ethic was only matched by her charismatic personality," Stivers said in a statement. "She represented her South Florida district well, and she will be dearly missed in Washington. I wish her and her family the best. I am confident we