By Tim Gaynor

PHOENIX (Reuters) - Remarks by a conservative Arizona Republican congressional candidate that Middle Easterners' "only goal in life is to cause harm to the United States" have sparked a dispute over whether the comments amount to hate speech.

Tea Party-backed Gabriela Saucedo Mercer, who was born in Mexico and is a naturalized U.S. citizen, won the Republican primary on Tuesday to run in an Arizona congressional district that flanks the Mexican border. She faces Democrat Raul Grijalva, a five-term incumbent, in the November general election.

Grijalva sparked the debate Tuesday when he circulated a video in which the Republican tells an interviewer that authorities the previous year nabbed 25,000 illegal immigrants who were other than Mexican nationals.

"That includes Chinese, Middle Easterners. If you know Middle Easterners, a lot of them they look Mexican or like a lot of people in South America - dark skin, dark hair, brown eyes, and they mix in," she said in the interview, recorded last year by WesternFreePress.com.

"And those people, their only goal in life is to cause harm to the United States. So why do we want them here, either legally or illegally?" she said.

Arizona has been in the national spotlight after a U.S. Supreme Court ruling in June allowed a controversial "show-your-papers" measure that permits police to ask anyone they stop for other reasons about their immigration status. The measure is part of a crackdown on illegal immigration signed in 2010 by Republican Governor Jan Brewer.

Backers said it was needed because of the federal government's failure to secure the state's porous border with Mexico, although opponents have slammed the law as a mandate for racial profiling.

Mercer is running on a platform of tighter border security, opposition to abortion and defense of gun rights. She has been endorsed by Brewer, Republican Secretary of State Ken Bennett and the Border Patrol union's Tucson chapter, among others.

Grijalva, a long-term opponent of the immigration crackdown, issued a release on Tuesday denouncing what he called Mercer's "reckless hate speech," and urged everyone who endorsed Mercer to "withdraw their support immediately."

NOT OPEN TO INTERPRETATION

"This is not a he-said, she-said question of interpretation. Her comments are reprehensible and deserve condemnation from every quarter. Anyone who continues to support her campaign should be asked whether they want someone with her views in Congress," he said in a statement.

Mercer's campaign slammed the video circulated by Grijalva as deceptive.

"In it, snippets ... were used to try to weave a deceptive anti-Middle Eastern message with particular attention placed on a mere fragment of footage used selectively to construct a false narrative," the campaign said in a statement released on Wednesday.

"It is fascinating in a time of economic uncertainty, rising food and gas costs, and job losses that the focus of Mercer's opponent appears to be more about creating an enemy where none is warranted than working on solutions for the ailing district."

Rep. Keith Ellison, the first Muslim American elected to Congress, said he was disappointed in Mercer's "decision to inject division and fear" into the congressional race.

The American-Arab Anti Discrimination Committee, a non-sectarian civil rights and civil liberties group, also weighed in on the debate, slamming Mercer's words, which it said "once again exemplifies the bigotry and racism rampant within the Republican Party, and politics as a whole."

The nonprofit group called on Republican Party leaders, including presidential candidate Mitt Romney, to condemn her remarks and "move away from the politics of hate and fear."

(Editing by Greg McCune, Cynthia Johnston and Eric Walsh)