The United States and South Korea have again vowed to make no concessions to North Korea in spite of Kim Jong Un’s recent threats of a nuclear strike.

US President Barack Obama and South Korean President Park Geun-Hye pledged a unified front against the belligerent state and reiterated a demand that the North abandon its nuclear program before engaging in new talks.

During a White House news conference with Park, Obama said they would refuse to reward “provocative behaviour” and would instead use the North’s threat to reinforce cooperation between the two countries.

The sentencing of Kenneth Bae, a US citizen arrested in North Korea for allegedly plotting to overthrow the regime, has also raised concerns that Pyongyang may use him as a bargaining chip to get concessions.

“If Pyongyang thought its recent threat would drive a wedge between South Korea and the United States or somehow garner the North international respect, today is further evidence that North Korea has failed again,” Obama said.

“The days when North Korea could create a crisis and elicit concessions – those days are over,” he added.

Tensions have waned as the North reportedly removed two medium range missiles from their launch site.