A US Army sentinel guarding the Tomb of the Unknown Soldier appeared to rebuke Defence Secretary Pete Hegseth's delegation on Wednesday after ​laughter could be heard as they climbed the steps of the ‌solemn site, according to a video of the incident. Hegseth, his wife and senior aides could be seen taking pictures and speaking to each other on the steps of the memorial at ​Arlington National Cemetery following a Veterans Day event. Immediately after the laughter, the ​sentinel moved toward the group and, from a distance, shouted toward ⁠them: "All visitors will maintain an atmosphere of silence and respect at all ​times." Sitting at the heart of Arlington National Cemetery, the Tomb of the Unknown Soldier ​is a sacred site and the grave of three unknown American service members, including one from World War One. It is widely known as a place for mourning and for reflection ​on military service, and sentinels guard the site 24 hours a day. Read: US House blocks bid to impeach Defence Secretary Hegseth Asked about ​the incident, which was first reported by CNN, chief Pentagon spokesperson Sean Parnell said in a ‌statement: "The ⁠Secretary and the entire Department have always honoured —and will always honour — the sacrifices our military men and women have made to keep America safe." "While commemorating this solemn day, a soldier correctly and respectfully reminded everyone to maintain decorum," Parnell said. Hegseth, a former ​Army National Guard ​soldier who served ⁠in Iraq, prevailed this week after the House of Representatives rejected a Republican lawmaker's effort to impeach him. At a rare Pentagon ​press conference on Tuesday hours before the vote, Hegseth called the ​impeachment ⁠effort a farce and defended his record, which includes championing the unpopular Iran war, launching strikes on suspected drug vessels in Latin American waters and firing senior military officers. Democrats ⁠who ​won control of both chambers of Congress last ​week have promised to investigate Hegseth for his stewardship of the US military and have not ruled ​out another impeachment effort.