SEOUL/UNITED NATIONS - North Korean state media warned the United States of a “super-mighty pre-emptive strike” after US Secretary of State Rex Tillerson said the United States was looking at ways to bring pressure to bear on North Korea over its nuclear programme.

US President Donald Trump has taken a hard line with North Korean leader Kim Jong Un, who has rebuffed admonitions from sole major ally China and proceeded with nuclear and missile programmes in defiance of UN Security Council sanctions.

The Rodong Sinmun, the official newspaper of the North’s ruling Workers’ Party, did not mince its words.

“In the case of our super-mighty pre-emptive strike being launched, it will completely and immediately wipe out not only US imperialists’ invasion forces in South Korea and its surrounding areas but the US mainland and reduce them to ashes,” it said.

Reclusive North Korea regularly threatens to destroy Japan, South Korea and the United States and has shown no let-up in its belligerence after a failed missile test on Sunday, a day after putting on a huge display of missiles at a parade in Pyongyang.

Tillerson told reporters in Washington on Wednesday that the United States was “reviewing all the status of North Korea, both in terms of state sponsorship of terrorism as well as the other ways in which we can bring pressure on the regime in Pyongyang.”

US Vice President Mike Pence, on a tour of Asian allies, has said repeatedly an “era of strategic patience” with North Korea is over.

US House of Representatives Speaker Paul Ryan said during a visit to London the military option must be part of the pressure brought to bear.

“Allowing this dictator to have that kind of power is not something that civilised nations can allow to happen,” he said in reference to Kim.

Ryan said he was encouraged by the results of efforts to work with China to reduce tension, but that it was unacceptable North Korea might be able to strike allies with nuclear weapons.

North and South Korea are technically still at war because their 1950-53 conflict ended in a truce, not a peace treaty. South Korea’s acting president, Hwang Kyo-ahn, at a meeting with top officials on Thursday, repeatedly called for the military and security ministries to maintain vigilance.

The defence ministry said US and South Korean air forces were conducting an annual training exercise, codenamed Max Thunder, until April 28. North Korea routinely labels such exercises preparations for invasion.

The North has said it has developed a missile that can strike the mainland United States, but officials and experts believe it is some time away from mastering the necessary technology, including miniaturising a nuclear warhead.

Meanwhile, the UN Security Council on Thursday strongly condemned North Korea’s latest missile test and threatened to impose new sanctions against Pyongyang for its “highly destabilizing behaviour.”

In a unanimous statement, the council demanded that North Korea “conduct no further nuclear tests,” saying Pyongyang’s “illegal missile activities” were “greatly increasing tension in the region and beyond.”

The council threatened to “take further significant measures including sanctions” to address the crisis of North Korea’s missile launches.

While previous statements have warned of further measures, the agreed text made specific mention of sanctions, signalling a tougher stance from the council. “If we have to start looking at sanctions or other actions, we will,” US Ambassador Nikki Haley told reporters.

The US-drafted statement was agreed upon after Russia insisted that language stressing the need to achieve a peaceful solution “through dialogue” was included in the final text. Moscow had blocked an earlier version of the statement - which comes after North Korea carried out a failed test on Sunday - even though China, Pyongyang’s ally, had expressed its support for it.

However, Russian charge d’affaires Petr Iliichev denied blocking the statement, saying the United States had broken off talks on a consensus position in an “abrupt manner.”

Council statements are adopted by consensus among all 15 members.

“At the end of the day we realized that North Korea is a problem,” Haley said.

“No one on the council wants to see North Korea move forward with any sort of testing or strikes,” she added, saying that the agreed statement makes that “very clear.”

The United States, which holds the rotating council presidency this month, has scheduled a ministerial-level meeting on North Korea next week, to be chaired by US Secretary of State Rex Tillerson.

While no resolution will be adopted during the April 28 session, the United States and its allies are expected to turn up the pressure on China to use its leverage to rein in Pyongyang.

The council has imposed six sets of sanctions on North Korea - two of which were adopted last year - to significantly ramp up the punitive measures and deny Kim Jong-Un’s regime hard currency revenue.

Pyongyang is seeking to develop a long-range missile capable of hitting the US mainland with a nuclear warhead, and has so far staged five nuclear tests, two of them last year.

US Vice President Mike Pence vowed on Wednesday that the United States would counter any North Korean attack with an “overwhelming and effective” response.