South Korea, US Wrap Up Annual War Drills; Trump Says Talk Not The Answer

South Korea and the United States were finishing annual war games on the Korean peninsula on Thursday amid high tension over North Korea's weapons programmes and a disagreement between US President Donald Trump and his defence secretary on how to respond.

A series of threats and missiles launches by North Korea, including one on Tuesday that flew over Japan, has fuelled a tense standoff with the United States and its Asian allies in recent weeks.

The drills, involving tens of thousands of US and South Korean troops, have been focused on computer simulations but reports highlighting the prospect of more "visible" demonstrations of US power in the region have circulated in the wake of Pyongyang's latest test.

Trump on Wednesday declared "talking is not the answer" to resolving the long-standing impasse with North Korea.

"The US has been talking to North Korea, and paying them extortion money, for 25 years," Trump, who just last week said North Korean leader Kim Jong Un was "starting to respect" the United States, wrote on Twitter. "Talking is not the answer!"

However, US Defence Secretary Jim Mattis, when asked by reporters just hours later if the United States was out of diplomatic solutions with North Korea, replied: "No."

"We are never out of diplomatic solutions," Mattis said before a meeting with his South Korean counterpart at the Pentagon. "We continue to work together, and the minister and I share a responsibility to provide for the protection of our nations, our populations and our interests."

Japanese Defence Minister Itsunori Onodera spoke to Mattis by phone on Thursday and agreed to keep putting pressure on North Korea in a "visible" form, Japan's defence ministry said.

Trump, who has vowed not to let North Korea develop nuclear missiles that can hit the mainland United States, had said on Tuesday "all options are on the table," a veiled reference to military force.

Sanction Options

The 15-member UN Security Council on Tuesday condemned the firing of the missile over Japan as "outrageous," and demanded that North Korea halt its weapons programme but the US-drafted statement did not threaten new sanctions.

Japan was pushing the United States to propose new UN Security Council sanctions, which diplomats said could target North Korea's labourers working abroad, oil supply and textile exports.

Diplomats expected resistance from Russia and fellow veto-wielding power China, particularly given new measures were only recently imposed after Pyongyang staged two long-range missile launches in July.

Asked if Japanese Prime Minister Shinzo Abe and Trump talked about restricting North Korea's fuel supply when the two spoke by telephone on Wednesday, Chief Cabinet Secretary Yoshihide Suga said an embargo on oil and oil related products would be one of the options.

A US ban on travel to North Korea comes into effect on Friday, curbing one of its few remaining supplies of foreign currency.

'Key Milestone'

Early in August, North Korea announced plans to fire four missiles into the sea near the US Pacific territory of Guam after Trump had warned it would face "fire and fury" if it threatened the United States.

The Pentagon's Missile Defense Agency and the crew of the guided-missile destroyer USS John Paul Jones conducted a "complex missile defense flight test" off Hawaii on Wednesday, resulting in the intercept of a medium-range ballistic missile target, the agency said.

The agency's director, Lieutenant General Sam Greaves, called the test "a key milestone" in giving US Navy Aegis Ballistic Missile Defense ships an enhanced capability, but did not mention North Korea.

The United States and South Korea are technically still at war with North Korea because their 1950-53 conflict ended in a truce, not a peace treaty. North Korea routinely says it will never give up its weapons programmes, calling them necessary to counter perceived American hostility.