U.S. envoy Tom Barrack told Lebanese journalists at a press conference at the country's presidential palace on Tuesday to "act civilized," sparking outcry and calls for an apology.

As journalists shouted questions after the U.S. delegation's meeting with President Joseph Aoun, Barrack stepped up to the podium in the packed room and said: "We're going to have a different set of rules... please be quiet for a moment."