North Korea staged its sixth and apparently most powerful nuclear test so far on September 3. South Korea says the USA military flew powerful bombers and stealth jets over the Korean Peninsula in joint drills with South Korean warplanes.
North Korea bitterly denounced new sanctions on its economy as "vicious, unethical and inhumane" and warned the measures would only accelerate progress on its nuclear weapons program, state media reported on Monday.
On Friday, North Korea fired a medium-to-long range Hwasong-12 missile over Japan a few hours after it threatened to "sink" its southeastern neighbor.
The Spanish government has asked North Korea's ambassador to leave Madrid before the end of the month.
"The two leaders also exchanged views on the current situation on the Korean Peninsula".
"In case the U.S. opts for confrontation and war... it will meet a terrible nuclear strike and miserable and final ruin", North Korea said.
Military options available to Trump range from non-lethal actions like a naval blockade aimed at enforcing sanctions to waging cyber attacks and positioning new US weaponry in South Korea, where the United States has 28,500 troops. "You will. So we have to assume, and as commander of Strategic Command I have to assume, that they have the bomb and they will have the capability to deploy it on an ICBM", Hyten said.
Meanwhile the USA and Chinese leaders have committed to "maximising pressure on North Korea", the White House has said.
Mattis said that the USA has military options available to counter North Korea that wouldn't necessarily create a grave risk of retaliation against Seoul.
Moon also sought to promote the 2018 Winter Olympic Games in South Korea's PyeongChang, requesting Italy's active support and participation in the event.
China accounts for about 90 percent of North Korea's trade and sends largely free crude oil shipments to the North. Beijing has been increasingly frustrated with North Korea's nuclear drive, but it still doesn't want the North to collapse and cause a wave of refugees to cross the border into China and American troops to move into North Korea.
"Developments in the peninsula nuclear issue up to this point prove that no matter whether it is military threats in words or in action, they can not promote and advance a resolution", the foreign ministry spokesman, Lu Kang, said.
China is the closest diplomatic and economic ally of North Korea, but last week joined forces with the rest of the UN Security Council states, voting for imposing the economic sanctions against Pyongyang.