Top US military officer Mark Milley says he was wrong to have accompanied President Donald Trump on a walk to a church through Lafayette Square, where he was photographed in his combat uniform with the presidential entourage.
"My presence in that moment and in that environment created a perception of the military involved in domestic politics," Mr Milley said in remarks to a National Defense University commencement ceremony.
"As a commissioned uniformed officer, it was a mistake that I have learned from, and I sincerely hope we all can learn from it."
Mr Trump's 1 June walk through the park to pose with a bible at a church came after authorities used pepper spray and flash bangs to clear the park and streets of largely peaceful protests.
Mr Milley said his presence and the photographs compromised his commitment to a military divorced from politics.
"I should not have been there," he said.
After protesters were cleared from the Lafayette Square area, Mr Trump led an entourage that included Mr Milley and Defense Secretary Mark Esper to St John's Episcopal Church, where he held up a bible for photographers and then returned to the White House.
President Donald Trump holds a Bible as he visits outside St. John's Church across Lafayette Park from the White House. Source: AP
Democratic presidential candidate Joe Biden voiced his own worries on Thursday, saying he believes President Donald Trump will try to "steal" the November election but he is confident soldiers would escort him from the White House if he loses and doesn't recognise the result.
"It's my greatest concern, my single greatest concern: This president is going to try to steal this election," Mr Biden said in an interview broadcast late on Wednesday on Comedy Central's The Daily Show.
Mr Biden did not specify how he thought Mr Trump, a Republican, might cheat. But the former vice president cited Mr Trump's opposition to mail-in voting and said Democrats would have lawyers present at voting locations across the country to look out for Republican efforts to suppress the vote.
Mr Trump has repeatedly attacked voting by mail, proclaiming without evidence that the expected increase in mail-in voting would lead to widespread fraud in the 3 November contest.
Mr Biden said recent comments by former senior military officials criticising Mr Trump's response to nationwide protests over police brutality made him confident the US military would intervene if Mr Trump refused to accept the election results.
"I'm absolutely convinced they will escort him from the White House with great dispatch," Mr Biden said.
Mr Biden has often said publicly he worries Mr Trump would try to cheat. But his rhetoric has escalated recently as most national polls show the former vice president leading the president, while Mr Trump has stepped up criticism of voting by mail.
Mr Trump's re-election campaign did not immediately respond to a request for comment. Mr Trump and his Republican allies say mail voting is prone to fraud and favours Democrats, even as numerous independent studies have found little evidence of either claim.
During the 2016 presidential election campaign, Mr Trump refused to say during a final debate with Democratic candidate Hillary Clinton that he would concede if Ms Clinton won.
Democratic presidential candidate, former Vice President Joe Biden. Source: AP
Election experts and officials expect a surge in mail-in voting this November due to concerns over the coronavirus pandemic, and warn the process could be marred by chaos of the type already seen in primary elections held in states during the viral outbreak.
Large number of mail ballots not delivered in time to be cast or counted could lead to legal challenges over election results. Counting mail ballots also take more time because a voter's identity must first be validated, raising the prospect that the election outcome won't be known well past Election Day, experts say.
A growing number of former senior military leaders have criticised the president over his handling of the civil unrest following the 25 May killing of George Floyd, a black man whose death in custody of the Minneapolis police set off protests for police reform and racial justice.
Former Defense Secretary Jim Mattis accused the president earlier this month of trying to divide America and roundly denounced a militarisation of the US response to civil unrest.
