NEW YORK (AP) — On a day of high-stakes diplomacy on the global stage, President Donald Trump began his United Nations visit by telling a prominent U.S. journalist, "You should not be here."

"It's an honor to be here," Trump said as he entered U.N. doors Tuesday ahead of his speech to the General Assembly and faced Kaitlan Collins of CNN, a frequent target of his ire. "I'm surprised that CNN is here covering me. You should not be here covering me. You said you weren't going to cover me."

As Collins n...