On Sunday night, the Trumps arrived at Nationals Park just before the first pitch of the Houston Astros-Washington Nationals match-up, just hours after the President announced that Islamic State (IS) leader Abu Bakr al-Baghdadi was killed in a US raid in northeast Syria, The Daily Mail reported.
Trump and Melania entered a lower-tier box to the left of home plate as the game got underway.
At that point his presence wasn't formally announced, but baseball fans in the section just below Trump's suite turned to look toward the box as he arrived. Some waved at the President as he smiled and gave a thumbs-up.
At the end of the third inning, ballpark video screens carried a salute to US service members that drew cheers throughout the stadium.
When the video cut to Trump and his entourage, cheers abruptly turned into a torrent of boos and heckling, with chants of "Lock him up" breaking out in some sections.
Footage captured by NBC News moments after the stadium announcer called out his name documented Trump's beaming smile drop sharply to a grimace when he first heard the boos ring out, The Daily Mail said in the report.
Trump then appeared to shake off the hostile reception, reclaiming his smile and waving enthusiastically to the crowd.
But the taunts continued throughout the game, with two fans behind the home plate unfurling signs that read "Veterans for Impeachment" at one stage.
But it was not immediately clear if the President, who left the venue at around 10 p.m., saw the sign.
( With inputs from IANS )