I do not draw red lines

US President Donald Trump chided North Korea for its recent missile tests, saying it is "behaving in a very very dangerous manner."

On the eve of what is likely to be a prickly G20 summit, with Trump facing animosity from traditional US allies, he used his keynote address in Warsaw to warn that a lack of collective resolve could doom an alliance that endured through the Cold War.

"It's a shame they're behaving this way -- they're behaving in a very, very dangerous manner and something will have to be done about it," Trump yesterday said in a news conference with Polish President Andrzej Duda.

The president said he has "some pretty severe things" available to him when asked about military action against North Korea, but declined to elaborate.

"As far as North Korea is concerned, I don't know, we will see what happens," Trump said when asked about military action against North Korea. "I have some pretty severe things that we are thinking about. That doesn't mean we are going to do it. I don't draw red lines."

Trump's comments came after North Korea launched what is believed to be its first test of an intercontinental ballistic missile Tuesday. US officials estimate it had a range of 3,400 miles, capable of hitting Alaska.

At a special meeting of the United Nations Security Council Wednesday, US Ambassador to the UN Nikki Haley warned military action was on the table in response to the test.

"The US is prepared to use the full range of our capabilities to defend ourselves and our allies," she said, adding the US would "prefer not" to use force. She called on China to use its economic influence over North Korea to rein in the regime of King Jong Un.

Meanwhile, Pyongyang warned it would be a "piece of cake" to destroy "gangster" South Korea, state media reported yesterday.

The test prompted the US and the South to stage a joint missile drill aimed at countering the North's threats, after South Korean President Moon Jae-In called for a response beyond "just words".

North Korea hit back Thursday, with its propaganda National Peace Committee for Korea criticising Moon for denouncing Pyongyang "instead of getting rejoiced over the praiseworthy event" staged by its northern neighbour, according to the KCNA news agency.

Mocking the South as "puppet military gangsters," the KCNA report added: "It will be as easy as a piece of cake for the (North) to wipe out the puppet forces ... as we are now able to destroy even the US mainland across the ocean."

The North's leader Kim Jong-Un described the ICBM launch -- staged on the US Independence Day holiday -- as a gift to "American bastard" and vowed to give more "gift packages" to the US in the future.

The impoverished North is already under onerous international sanctions imposed over its past nuclear and missile tests held in violation of UN resolutions, which ban it from using any ballistic or nuclear technologies.

The EU and Japan yesterday called for further sanctions against North Korea for repeated violation of UN resolutions.

EU president Donald Tusk said after talks with Japanese Prime Minister Shinzo Abe in Brussels on a landmark free trade accord that both sides shared basic values about how a rules-based global order should work.

China meanwhile warned against "words and deeds" that could heighten tensions over North Korea and pressed again for negotiations.