Trump on Twitter: 'North Korea Is Behaving Very Badly'

North Korea is behaving very badly. They have been "playing" the United States for years. China has done little to help!

— Donald J. Trump (@realDonaldTrump) March 17, 2017

Trump's tweet comes amid Secretary of State Rex Tillerson's visit to South Korea where he said "nothing is off the table" when it comes to the United States' response to North Korea's aggressive stance lately - including nuclearizing the peninsula if necessary.

North Korea has accelerated its weapons development, violating multiple U.N. Security Council resolutions and appearing undeterred by tough international sanctions. The North conducted two nuclear test explosions and 24 ballistic missile tests last year. Experts say it could have a nuclear-tipped missile capable of reaching the U.S. within a few years.

The Associated Press contributed to this report.

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