U.S. President Donald Trump on Sunday called out "Mr. Chairman" Kim Jong Un on Twitter, urging the North Korean leader to "act quickly" to get a deal done as he is the "only one" who can deliver what Pyongyang needs.

President Trump's overture to the DPRK leader, which appeared to be his first public outreach to Kim Jong Un since August, follows weeks of increasing tensions, insults, and threats between Washington and Pyongyang over nuclear negotiations, sanctions relief, and military drills.