Gosar criticized McSally in his announcement, saying “we cannot afford another establishment patsy who promises one thing and votes differently,” AZCentral reported.
Gosar said while he liked McSally personally, he found her to be “inconsistent politically.”
“None of us can count on Martha keeping a campaign promise as she will fall for whatever the D.C. elite tells her to do at the time. I have seen that firsthand,” he said.
McSally’s spokeswoman Torunn Sinclair criticized Gosar's voting record, saying she supported President Donald Trump's agenda more than Gosar did.
“The fact is Congresswoman McSally votes with the president 97 percent of the time while Congressman Gosar only votes with the president 77 percent of the time,” Sinclair said. “If he voted with the president as much as Martha, we could accomplish even more for Arizonans.”
Ward and McSally are competing against each other along with former Maricopa County Sheriff Joe Arpaio for the Republican nomination for Arizona’s senate seat. Sen. Jeff Flake is retiring in 2019.
Ward also has the backing of former White House political strategist and Breitbart executive Steve Bannon and Republican megadonor Robert Mercer, who contributed $500,000 to a super PAC supporting Ward, Politico reported Monday.
Some in the Republican establishment fear a Ward win would lessen the chances of the GOP keeping the seat. Rep. Kyrsten Sinema is the front-runner in the Democratic primary.
Polls have shown McSally leading the Republican race ahead of Ward and former Maricopa County Sheriff Joe Arpaio.
A member of the conservative House Freedom Caucus, Gosar is also known for pulling ostentatious stunts and making xenophobic remarks.
During this year’s State of the Union, Gosar asked Capitol Police to arrest “illegal aliens” since many Democrats invited undocumented immigrants to the address.
Over the weekend, Gosar traveled to London for a rally to support Tommy Robinson, a far-right activist who has frequently made divisive and inflammatory remarks about Islam.
Gosar criticized “disgusting and depraved individuals” who commit acts of sexual violence from Muslim communities, Phoenix New Times reported.
“We know these men come from commonly Pakistani, Bangladeshi, and Muslim backgrounds,” the newspaper reported Gosar.
Correction 2:37 pm.| A previous version of this story misstated Sinclair's employer.