BOSTON (AP) — Massachusetts's special U.S. Senate election heads into its final stretch after Republican Gabriel Gomez and Democratic U.S. Rep. Edward Markey engaged in some testy exchanges during their final debate.

The match-up Tuesday, sponsored by a consortium of Boston media outlets, came less than one week before the June 25 election. The candidates sparred on taxes, drones and guns during the one-hour meeting at the WGBH-TV studios.

One of the sharpest confrontations came on the question of term limits.

Gomez said he told veteran Republican Sen. John McCain of Arizona, who campaigned for Gomez in Boston last month, that he should leave the Senate at the end of his term.

"Mr. Gomez did not tell John McCain that this is his last term," said Markey. "That did not happen."

"It absolutely did happen," said Gomez, who has proposed a two-term limit for members of the Senate and has pledged not to serve more than two full terms in Washington.

Markey said after the debate that he was not accusing Gomez of lying, but that he still had trouble believing that it had happened as Gomez explained.

Gomez told reporters McCain had indicated his support for term limits.

Brian Rogers, a spokesman for McCain, said in an e-mailed statement to the Associated Press that McCain and Gomez discussed term limits during the visit, but on that particular issue McCain disagreed with Gomez.

Earlier in the debate Gomez tried to blunt criticism that he has failed to release a list of clients he worked for while at the private equity firm Advent International.

Gomez pointed to President Barack Obama, saying Obama's pension fund from his years as an Illinois lawmaker is invested in part with the company.

"You should ask President Obama if he is happy ... with what we have done at Advent International," Gomez said.

The White House did not immediately have a comment.

Markey said Gomez should release even more information about companies he worked with at the firm.

"My vote record is completely transparent," Markey said. "But with Mr. Gomez, we still don't know who his clients are."

Markey also defended his role in obtaining millions in tax dollars for a planned transformation of a polluted industrial site along the Malden River into a telecommunications center with the promise of thousands of jobs.

The jobs never materialized, but Markey said the project was still a benefit to neighboring communities because it cleaned up a blighted area.

The candidates also weighed in on the use of drones.

Gomez, a former Navy SEAL, said that while he would be very hesitant about using drones to target citizens on U.S. soil, that wouldn't apply to American citizens outside of the country who have "switched sides."

"Overseas, absolutely if you've changed sides, if you're an American, you're a vital target," Gomez said.

Markey also endorsed the use of drone strikes overseas if the target is a threat to the national interest. He also said drones will pose an increasing privacy threat within the U.S. in coming years as thousands take to the air.

"We have to make sure that as those drones take off that they are accompanied by privacy protections," said Markey.

During a segment of the debate in which the candidates were allowed to question each other, Gomez, who said Markey voted to raise taxes 300 times, asked Markey if he had ever opposed a tax supported by his party. Markey responded that he had voted to reduce taxes to middle class citizens by $1 trillion and opposed tax breaks for big business.

Gomez pointed to Markey's past support for a tax on medical device companies that was included in Obama's 2010 federal health care law.

Markey again brought up Gomez's opposition to a federal ban on assault weapons and high-clip magazines, asking the Republican why an ordinary citizen would need to buy a gun that could shoot 100 rounds in two minutes.

Gomez did not respond directly to the question but pointed to his support for a bill that would broaden background checks, accusing Markey of misrepresenting his position and using the Newtown, Conn., school massacre for political gain.

"You will do anything and say anything to get elected," Gomez said. "You've been doing that for 37 years."

Gomez also said he's unfazed about polls showing he's trailing Markey.

"I've been the underdog my whole life," Gomez said after the debate. "You saw the comeback of the underdog begin today in earnest."

Markey and Gomez are vying for the seat formerly held by John Kerry, who resigned to become U.S. Secretary of State.

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Associated Press writer Steve Peoples contributed to this report.