Dallas megachurch pastor Robert Jeffress gave the opening prayer Monday at the controversial opening of the U.S. Embassy in Jerusalem.

The pastor of First Baptist Dallas has been a vocal supporter of President Donald Trump and said that he had "courage that no other U.S. president has" had to move the embassy from Tel Aviv.

Jeffress' role at the ceremony was criticized by former GOP presidential candidate Mitt Romney, who called the pastor a bigot for his record of remarks slamming other faiths.

On Monday, Jeffress stood next to Rabbi Zalman Wolowik of New York and closed his eyes in prayer.

The pastor lauded Israel's Prime Minister Benjamin Netanyahu "and his determination to do whatever it takes to protect his people, at all cost."

Jeffress also complimented the U.S. ambassador to Israel, David Friedman, and heaped praise on Trump's "tremendous leadership."

"I believe, Father, I speak for every one of us when we say we thank you every day that you have given us a president who boldly stands on the right side of history, but more importantly, stands on the right side of you, oh God, when it comes to Israel," the pastor said.

As the embassy was opening, 52 Palestinians were killed by Israeli gunfire in mass protests along the Gaza border. At least 1,200 others were shot and wounded, according to Gaza's ministry of health. The protests were, in part, against the U.S. decision to move the embassy.

The violence marked the deadliest day in Gaza since a 2014 war with Israel.

Jeffress previewed his appearance at the embassy opening during an interview last week on the show Fox & Friends, where he is a regular guest.

"This is a historic moment because it represents the United States recognizing Jerusalem as the capital of Israel, something that the Bible and secular history have told us for 3,000 years," he said.

Trump has been criticized for announcing plans to relocate the embassy and for formally recognizing Jerusalem as Israel's capital. Palestinians and Israelis both claim Jerusalem as their capital, and U.S. presidents have historically declined to weigh in on the dispute over the city.

Watch my interview from @foxandfriends on @FoxNews as I discuss my part in the opening of the United States Embassy in Jerusalem on Monday. https://t.co/d9fmjF1YhX — Dr. Robert Jeffress (@robertjeffress) May 12, 2018

"Today there are many devout Jews and devout Christians alike who are saying, 'Thank God we have a president like Donald Trump who is willing to stand on the right side of history and the right side of God on this issue,'" Jeffress said on Fox.

Romney, a Senate candidate and former governor of Massachusetts, condemned Jeffress' selection Sunday night in a tweet.

Robert Jeffress says “you can’t be saved by being a Jew,“ and “Mormonism is a heresy from the pit of hell.” He’s said the same about Islam. Such a religious bigot should not be giving the prayer that opens the United States Embassy in Jerusalem. — Mitt Romney (@MittRomney) May 14, 2018

"Robert Jeffress says 'you can't be saved by being a Jew,' and 'Mormonism is a heresy from the pit of hell,'" Romney, a Mormon, said. "He's said the same about Islam. Such a religious bigot should not be giving the prayer that opens the United States Embassy in Jerusalem."

Jeffress endorsed Romney for president in 2012 after calling the Mormon Church a "cult." Jeffress also said President Barack Obama was "paving the way for the future reign of the anti-Christ."

An hour after Romney's tweet, Jeffress responded on Twitter saying that "Christianity has taught for 2,000 years that salvation is through faith in Christ alone."

"The fact that I, along with tens of millions of evangelical Christians around the world, continue to espouse that belief, is neither bigoted nor newsworthy," said Jeffress, who leads a congregation of about 12,000.

Historic Christianity has taught for 2,000 years that salvation is through faith in Christ alone. The fact that I, along with tens of millions of evangelical Christians around the world, continue to espouse that belief, is neither bigoted nor newsworthy. — Dr. Robert Jeffress (@robertjeffress) May 14, 2018

Dallas-area Imam Omar Suleiman, president of the Yaqeen Institute for Islamic Research, also questioned the choice of Jeffress to lead a prayer at the ceremony in Jerusalem.

"Waiting for all you woke Dallas folks and progressives to be outraged," he tweeted.

Dallas Pastor Robert Jeffress will be leading the prayer at the declaration of the new Jerusalem embassy tomorrow. Waiting for all you woke Dallas folk and progressives to be outraged. — Omar Suleiman (@omarsuleiman504) May 12, 2018

In a 2010 lecture series called "Politically Incorrect," Jeffress blasted the theory of evolution and preached that non-Christians were bound for eternal damnation.

"God sends good people to Hell," he said. "Not only do religions like Mormonism, Islam, Judaism, Hinduism--not only do they lead people away from from God, they lead people to an eternity of separation from God in Hell. You know Jesus was very clear: Hell is not only going to be populated by murderers, and drug dealers, and child dealers; Hell is going to be filled with good religious people who have rejected the truth of Christ."

Other Jeffress remarks have elicited backlash over the years. He called Islam a "false religion" that is "inspired by Satan" and gave a speech titled "Why Gay Is Not OK" that sparked a protest at the downtown Dallas church.

Sen. Ted Cruz of Texas also attended Monday's ceremony.

The Associated Press contributed to this report.