While stressing that the United States remains "in a diplomatic effort engaging allies and partner nations across the board", Mattis said that the USA military stands ready to provide options if they are necessary. But, he added, sanctions "should not harm the livelihood and normal humanitarian need of the DPRK", using the initials of North Korea's official name.
This comes after the USA on Tuesday warned it is ready to use force if needed to stop the country's nuclear missing program.
"Diplomacy has not failed", said Mattis.
"I think it was Russian Federation, I think it could have been other countries", Trump said.
He said North Korea was behaving in a "very, very unsafe manner" and that something would have to be done about it. "We stand ready to provide (military) options if they are necessary".
"I don't believe this capability in itself brings us closer to war", Mattis told reporters Thursday at the Pentagon.
"We remain in a diplomatic effort engaging allies and partner nations across the board". "This mission clearly demonstrates the U.S. -ROK alliance remains prepared to use the full range of capabilities to defend and to preserve the security of the Korean Peninsula and region".
During his meeting with Chinese leader Xi Jinping at the G-20 summit in Hamburg, Trump appeared willing to give China more time.
China called on Thursday for restraint and made clear it did not want to be targeted by U.S. sanctions.
"It's gonna be fine, I think", Lee said. North Korea has also conducted six underground nuclear tests, the latest one coming in September 2016.
Over dinner, Japanese Prime Minister Shinzo Abe "conveyed approval" for USA sanctions against Chinese companies that deal with with North Korea and said the Japanese government also has been monitoring the movements of those businesses, according to Maruyama. He was due to meet with Xi there.
"Trade between China and North Korea grew nearly 40% in the first quarter". "Trade between China and North Korea grew nearly 40%... so much for China working with us - but we had to give it a try!" Yet China has called for a measured approach and has been slow to act, irritating Trump enough to tweet that if Beijing doesn't step in, the United States will go it alone.
President Moon Jae-in and Japanese Prime Minister Shinzo Abe have agreed to work towards a peaceful resolution of North Korea's nuclear threat.