The Blue House also emphasized support for continued joint military exercises with the U.S.
He said: 'We'll know it when we see it.
But Tillerson says it's not as simple as North Korea stopping launches for a few days or weeks.
For the USA, it was a long-awaited sign of progress for Trump's strategy of trying to enlist Beijing's help to squeeze North Korea diplomatically and economically.
The US-drafted resolution bans North Korean exports of coal, iron, iron ore, lead, lead ore and seafood following Pyongyang's two intercontinental ballistic missile tests in July.
U.S. Secretary of State Rex Tillerson says the best signal North Korea could give that it's prepared for negotiations with the U.S. would be to halt its missile launches.
They urged rival claimant states in the South China Sea "to refrain from land reclamation, construction of outposts, militarization of disputed features, and undertaking unilateral actions that cause permanent physical change to the marine environment in areas pending delimitation".
The united states and china piled pressure on north Korea Sunday to abandon its nuclear missile programme after the un security council approved tough sanctions which could cost Pyongyang $1 billion a year.
Authorities arrest Northwestern professor, Oxford employee wanted in Chicago murder
Chicago Police spokesman Anthony Guglielmi announced the development on Twitter, writing: "CPD has gotten word that Prof". Guglielmi said in an email Thursday that the men are at-large but "we have an idea of their whereabouts".
"The difference we've got is a new president in the United States, who does things differently for better or for worse than any of his predecessors and seems to be not quite in the same language as the North Koreans".
Trump tweeted that he was "very happy and impressed with 15-0 United Nations vote" on the sanctions.
North Korea's open flouting of United Nations rules with its missile launches meant that it had to be punished, but sanctions had to be precisely targeted, said in the front page commentary of the overseas edition of the ruling Communist Party's official People's Daily newspaper.
A White House statement said US President Donald Trump and his South Korean counterpart Moon Jae-In spoke on the phone on Sunday and agreed Pyongyang "poses a grave and growing direct threat".
The two ministers shook hands before speaking, Yonhap said.
The White House released a statement Monday on the call between Trump and Moon that said, "The leaders committed to fully implement all relevant resolutions and to urge the global community to do so as well". Even so, the US would prefer to resolve the threat "short of what would be a very costly war in terms of the suffering of, mainly, the South Korean people", McMaster said.
SMITH: The U.S. and the United Nations have been imposing sanctions on North Korea for years. Tensions flared alarmingly in recent years over China's island-building works in one of the most-contested regions, where US naval and aerial "freedom of navigation" patrols have challenged Beijing's claims.