Tensions were on the rise Sunday ahead of the largest ever US-South Korea air exercise, with Pyongyang calling it an "all-out provocation" that could lead to nuclear conflict as a US lawmaker warned of a growing likelihood of "preemptive war" on the divided peninsula.

The five-day Vigilant Ace drill -- involving some 230 aircraft including F-22 Raptor stealth jet fighters -- begins Monday, five days after the North test-fired an intercontinental ballistic missile believed to be capable of hitting the US mainland in a new challenge to President Donald Trump.

The North's ruling party Rodong newspaper slammed the upcoming drill.

"It is an open, all-out provocation against the DPRK, which may lead to a nuclear war any moment," it said in an editorial Sunday, using the North's official name.

"The US and South Korean puppet warmongers would be well advised to bear in mind that their DPRK-targeted military drill will be as foolish as an act precipitating their self-destruction," it said.

The commentary was published a day after Pyongyang's foreign ministry accused the Trump administration of "begging for nuclear war" by staging what it called the reckless air drills.

- 'Preemptive war' -

In Washington, meanwhile, an influential Republican lawmaker joined National Security Advisor HR McMaster in warning that time is running out on diplomatic efforts to rein in North Korea's nuclear and missile programs.

Senator Lindsey Graham, a foreign policy hawk, told CBS' "Face the Nation" the United States moves closer to "preemptive war" with every new North Korean missile or nuclear test.

"If there's an underground nuclear test, then you need to get ready for a very serious response by the United States," Graham said.

North Korea has boasted -- and Western experts agree -- that the Hwasong-15 missile tested on Wednesday is capable of reaching the United States, raising the prospect of a direct nuclear threat to Washington.

Graham's remarks echoed those of McMaster, who told a security forum in Washington on Saturday that the potential for war with North Korea "is increasing every day."

"We are in a race to be able to solve this problem," McMaster said. "This would be the most destabilizing development I think in the post-World War II period. It's something that places us at direct risk but places the world at risk."

The United States has demanded tougher international sanctions in response to the latest missile tests, including cuts in oil shipments to the isolated state.

Graham said he has had extensive discussions with the Trump administration about the situation.

US policy, he said, is "to deny North Korea the capability to hit America with a nuclear-tipped missile. Not to contain it."

"Denial means preemptive war as a last resort. That preemption is becoming more likely as their technology matures. Every missile test, every underground test of a nuclear weapon, means the marriage is more likely.

"I think we're really running out of time. The Chinese are trying, but ineffectively," he said.

Beijing has backed a slew of sanctions that include bans on imports of North Korean coal, iron ore and seafood.

But it has refused to turn off its pipeline shipping crude to North Korea.

North Korea, meanwhile, has been on a tear, undeterred by international pressure.

In September, it conducted its sixth and most powerful nuclear test.

The North says the Hwasong-15 missile can be tipped with a "super-large heavy warhead" capable of striking the whole US mainland.

But analysts remain unconvinced that it has mastered the advanced technology to allow the rocket to survive re-entry to the Earth's atmosphere.

Source:AFP