WASHINGTON (AFP) - The senior US diplomat for Asia, Susan Thornton, said on Thursday (Feb 15) she understood the Trump administration had no strategy for a so-called bloody nose strike on North Korea, but Pyongyang would be forced to give up its nuclear weapons "one way or another."

President Donald Trump's administration says it prefers a diplomatic solution to the crisis over North Korea's development of nuclear missiles capable of hitting the United States.

But US officials have told Reuters and other media that Trump and his advisers have discussed the possibility of a limited strike on North Korea that would neither knock out its program nor overthrow leader Kim Jong Un's government.

Such talk of a "bloody nose" strike has alarmed Korean experts who said that this could trigger catastrophic retaliation, but it has died down since North and South Korea resumed talks last month and North Korea joined the Winter Olympics in South Korea.

Two US senators, a Democrat and Republican, who spoke at Thornton's confirmation hearing for the post of assistant secretary for East Asia, said they and other senators had been told by senior White House officials on Wednesday that there was no such strategy.

Asked by Democratic Senator Jeanne Shaheen if the Trump administration had no "bloody nose" strategy, Thornton replied:"That is my understanding, senator, yes."

Republican Senator James Risch said the lawmakers had been told "by administration people, about as high up as it gets, that there is no such thing as a 'bloody nose strategy.'"

Risch added that the officials said they had never considered it or talked about it.

Thornton, currently the acting assistant secretary for East Asia, said Washington was open to talks with Pyongyang but that North Korean denuclearisation would be the only issue.

"Our preference is to achieve denuclearisation of the Korean Peninsula through a diplomatic settlement, but we will reach this goal one way or another," Thornton said.

North Korea has repeatedly rejected calls to abandon its nuclear weapons programme.

Thornton said the State Department was working "very hard" with the White House on a nomination for the post of US ambassador to South Korea, which has been vacant for a year.

The White House said this month it is no longer considering Victor Cha, a former official who has questioned the wisdom of a preventative military strike.

Cha said such a strike carried too great a risk of leading to war.