WASHINGTON (AP) — With North Korea, President Donald Trump puts on the charm. But with Iran, he cranks up the pressure with economic sanctions and a stronger military presence in the Persian Gulf. He has warned its leaders they are "playing with fire."

Nuclear weapons are at the heart of the difficult U.S. relations with both Pyongyang and Tehran. But it's in North Korea where Trump has more leeway and perhaps a greater chance of striking a deal.

Kim Jong Un has seemed as willing to meet with Trump as the U.S. president has been to talk and shake hands for the cameras with him. The North Korean leader jumped at the chance to meet Trump at the Demilitarized Zone between the Koreas last weekend.

Trump has made repeated overtures to Iranian leaders, too, but without the same results.

"I think Trump would be equally on a charm offensive with the Iranians if he had a dance partner," said Mark Dubowitz, an Iran nuclear deal skeptic with the Foundation for Defense of Democracies.

Also, Israel, which views Iran as its archenemy, is pressuring Trump to take a hard-line approach to Tehran, which has threatened to wipe Israel off the map. There is no big anti-North Korea lobby in the United States pressuring the White House to shun Kim's repressive government.