US has said, it has no intention of toppling the North Korean regime, but warned that Pyongyang must halt its nuclear missile program. <br/><br/>US Secretary of State Rex Tillerson told this to reporters in Washington on diplomatic efforts to put pressure on North Korea. <br/><br/>Mr Tillerson said, Washington is willing to talk to Pyongyang if its leaders are ready to abandon the nuclear weapons. He said, US is not posing a threat to North Korea, rather Pyongyang is presenting an unacceptable threat to Washington and it has to respond.