The preparations come amid a tense escalation of threats between the USA and North Korea over the latter's recent gains in nuclear weapons technology and its successful launch of an intercontinental ballistic missile that theoretically could hit cities on the east coast of the United States.
But a senior official familiar with negotiations between the United States and China said "it was not an accident or a mistake that Tillerson did not mention nuclear testing".
With the regime's latest long-range ballistic missile tests, North Korea's Foreign Minister Ri Yong-ho was again isolated from the sole multilateral forum Pyongyang takes part in.
The Trump administration's attempts to pressure North Korea into abandoning its nuclear and missile ambitions have so far gained little traction, and Pyongyang has only stepped up its tests, launching two ICBM tests last month.
China "hopes North Korea can echo this signal from the United States", Wang added.
China, North Korea's lone major ally, has repeatedly said it is committed to enforcing increasingly tough United Nations resolutions on North Korea, though it has also said what it terms "normal" trade and ordinary North Koreans should not be affected.
The question of whether Beijing would go along with much harsher sanctions against North Korea was answered this weekend.
"It would be a very costly war, in terms of... in terms of the suffering of mainly the South Korean people", he said.
British surveyors report slowing house price growth
However, on Wednesday, Ulster University's latest Quarterly House Price Index report said there had been a 1.1% fall in values. Two-thirds of those surveyed reported that homes marketed at more than £1m had sold for less than their original asking price.
Mr Tillerson, who held separate talks in Manila with foreign ministers Wang Yi of China and Sergei Lavrov of Russian Federation on Sunday, also sought to emphasise a united stance against the North.
Tillerson said Washington would not "specify a specific number of days or weeks" before deciding that North Korea had indeed stopped its tests.
North Korea says its ICBMs are a legitimate means of defense. "Can we get to the point where the North Koreans do not see the necessity of having nuclear weapons?"
U.N. Security Council Resolution 2371 bans all North Korean exports of coal, iron, lead, and seafood, sets limits on the number of North Korean workers overseas, restricts joint-venture investments, and freezes assets and restricts shipping, potentially reducing North Korea's $3 billion export revenue by roughly one-third.
The Korean Central News Agency warned that the USA will "pay the price for its crime ... thousands of times" and threatened to teach the US a "decisive act of justice".
"Just completed call with president Moon of South Korea".
The ministers met in the Philippines' capital on the sidelines of the ASEAN forum.
"After many years of failure, countries are coming together to finally address the dangers posed by North Korea".