Defense Secretary Mark Esper and Gen. Mark Milley, chairman of the Joint Chiefs of Staff, were caught by surprise Monday night when they were led to St. John’s Episcopal Church in Washington in a staged visit for President Donald Trump, a defense official said.

Esper and Milley were among a group of White House officials and aides who followed Trump as he walked across Lafayette Park to the historic church after officers in riot gear used tear gas and flash bangs to clear the area of peaceful protesters.

“Their understanding is they were going into Lafayette Park to review the efforts of the troops,” the official said of Esper and Milley.

Milley and Esper were on their way to the FBI’s Washington field office to monitor protests with Attorney General William Barr and FBI Director Christopher Wray when they were diverted to the White House to update the president. After the briefing, Trump delivered an address in the Rose Garden in which he threatened to deploy the military to quell the unrest over the police-involved death of George Floyd in Minneapolis.

Trump ended the speech by saying he was going to pay his respects “to a very, very special place,” but he didn’t elaborate.

The official said Trump, who held up a bible for a photo-op at the church, did not walk out of the White House with it, so they had no advance warning. Esper and Milley were also not aware that the officers used tear gas to force the protesters out of the area, the official said.

“They were not aware that park police and law enforcement made the decision to clear the square,” the official said.

The White House did not respond to a request for comment.

Trump’s visit to St. John’s church came a day after it was vandalized amid chaotic demonstrations triggered by the death of Floyd.

The photo-op sparked outrage from lawmakers and religious leaders, including the bishop of the Episcopal Diocese of Washington.

The Rev. Mariann Budde, bishop of the Washington diocese, said Trump’s staged visit to St. John’s “was an abuse of the spiritual tools and symbols of our traditions and of our sacred space.”

“He didn’t come to church to pray, he didn’t come to church to offer condolences to those who are grieving,” Budde said Tuesday in an interview with Craig Melvin on NBC’s “TODAY” show. “He didn’t come to commit to healing our nation, all the things that we would expect and long for from the highest leader in the land.”

Several former military officials criticized Milley for appearing on the streets of Washington in combat fatigues amid mass protests.

Sources told NBC News that Trump’s unannounced walk to the church “was his idea” because he “wanted the visual.” The president was frustrated by news reports that Secret Service officers ushered him to the White House bunker during Friday night’s unrest, the sources said.