Donald Trump has continued his tough rhetoric on North Korea, stating on Sunday that negotiations with Kim Jong Un were a “waste of time” and promising he would “not fail” to deal with the situation.

Taking to social media on Twitter, the president once again hit out at the North Korean leader in a series of tweets on Sunday.

“Being nice to Rocket Man hasn't worked in 25 years, why would it work now? Clinton failed, Bush failed, and Obama failed. I won't fail,” Trump wrote on Twitter on Sunday, in comments that appeared to leave out the detail that Kim Jong Un only took over from his father six years ago.

His tweet was met with mixed reactions on social media, with some users praising Trump for his tough-talking reaction to the situation with North Korea, while others suggested the president did not appear to know how long Kim Jong Un had been in power and said he appeared to be looking to start a war.

“It's like you'd truly prefer nuclear war to negotiations,” Steven Boyer wrote in response to Trump’s tweet. “You're an idiot monster.”

Earlier in the day, the president also addressed comments made by Secretary of State Rex Tillerson that he remained in discussions with officials in North Korea, despite there being no official relationship between Pyongyang and Washington, The Hill reported.

“I told Rex Tillerson, our wonderful Secretary of State, that he is wasting his time trying to negotiate with Little Rocket Man,” Trump tweeted.

"Save your energy Rex, we'll do what has to be done!" he added.

The president has not shied away from entering into a war of words with the isolated nation and has not ruled out military action over North Korea; previously promising to respond to threats from the country with “fire and fury,” in comments that were criticized by lawmakers from both parties for being overly provocative.