Washington: US President Donald Trump said on Thursday he would prefer not to use military action against North Korea to counter its nuclear and missile threat but that if he did it would be a ‘very sad day’ for the leadership in Pyongyang.

Trump again pointedly declined to rule out a US military response following North Korea’s sixth and most powerful nuclear test as his administration seeks increased economic sanctions, saying Pyongyang was ‘behaving badly and it’s got to stop.’

‘Military action would certainly be an option. Is it inevitable? Nothing is inevitable,’ Trump said during a news conference.

I would prefer not going the route of the military,’ Trump said. ‘If we do use it on North Korea, it will be a very sad day for North Korea.’

Even as Trump has insisted that now is not the time to talk to North Korea, senior members of his administration have made clear that the door to a diplomatic solution remains open, especially given the US assessment that any pre-emptive strike would unleash massive North Korean retaliation.

While Trump talked tough on North Korea, China agreed on Thursday that the United Nations should take more action against Pyongyang but also kept pushing for dialogue to help resolve the standoff.

North Korea, which is pursuing its nuclear and missile program in defiance of international condemnation, said it would respond to any new UN sanctions and US pressure with ‘powerful counter measures’, accusing the United States of aiming for war.

The United States wants the UN Security Council to impose an oil embargo on North Korea, ban its exports of textiles and the hiring of North Korean labourers abroad, and to subject leader Kim Jong Un to an asset freeze and travel ban, according to a draft resolution seen by Reuters on Wednesday.

Pressure from Washington has ratcheted up since North Korea conducted its nuclear test on Sunday. That test, along with a series of missile launches, showed it was close to achieving its goal of developing a powerful nuclear weapon that could reach the United States.

‘Given the new developments on the Korean peninsula, China agrees that the UN Security Council should make a further response and take necessary measures,’ Chinese Foreign Minister Wang Yi told reporters.

‘Any new actions taken by the international community against the DPRK should serve the purpose of curbing the DPRK’s nuclear and missile programmes, while at the same time be conducive to restarting dialogue and consultation,’ he said, referring to North Korea by the initials of its official name, the Democratic People’s Republic of Korea.

China is by far North Korea’s biggest trading partner, accounting for 92 percent of two-way trade last year. It also provides hundreds of thousands of tonnes of oil and fuel to the impoverished regime.

Trump has urged China to do more to rein in its neighbour, which was typically defiant on Thursday.