With regional leaders seeking how to square US President Donald Trump's "America First" doctrine with a US leadership role in the region, Mattis strongly reaffirmed US commitment to its alliances.
The defense chief spoke directly to concerns that the United States might grant concessions to China to ensure its cooperation on North Korea, saying the issue was not "binary" and that the U.S. would continue to pressure Beijing elsewhere.
He also said he believed China, North Korea's closest ally, will ultimately see Pyongyang as a liability.
The UN Security Council has extended its sanctions against North Korea with a resolution that adds more individuals and groups to the list.
Mattis added that the USA is "working with China on North Korea because that is also a problem for China".
'Dead Woman Walking': Amid Election Fallout, Theresa May Stands On Shaky Ground
The party came together around a brilliant manifesto and came together for a result that you and many others never expected. If a coalition of minority parties led by Labor effectively opposes May's government, a new election could be triggered.
China has actively advocated new thoughts on settling complex hotspot issues in the region, He said. "Our two countries can and do cooperate for mutual benefit".
In a tough speech after the vote, US Ambassador Nikki Haley said: "The Security Council is sending a clear message to North Korea today: Stop firing ballistic missiles or face the consequences".
Mattis noted that this week the Pentagon conducted what it called a successful test of its missile defense system, which is being developed mainly with North Korea in mind.
"Secretary Mattis thanked Singapore for its support, which has helped to enable the United States presence in the Asia-Pacific region", Ross said.
The pair of Japanese Naval Vessels and US Aircraft carriers have introduced a joint drill in the Sea of North Korea on Thursday.
In his speech, Mattis acknowledged the hard diplomacy involved in getting China to act against North Korea, a longtime trade partner that shares a border. It allegedly works with a North Korean trading company, Tangun, which the USA accuses of securing supplies for the nuclear program.
NSA chief, intelligence director won't comment on Trump conversations
Coats was a member of the Senate Intelligence Committee in the late 1990s and from 2011 through a year ago . The two refused to comply with the request, which they regarded as inappropriate, the Post report said.
"For me, the troubling thing is I don't know what the strategic plan of the United States is", Cohen added.
The Taiwan Relations Act was passed after U.S. President Jimmy Carter recognized China and allows Washington to sell defensive weapons to Taiwan.
The first sign of cooperation between the two powers was evident in the United Nations Security Council's expanded targeted sanctions against Kim Jong-un's regime.
The issue arose briefly during questions from his audience, but Mattis did not address it directly.
"If it continues on this risky path, we will have no other choice but to reinforce the pressure, again and again", Delattre said.
Numerous delegates and participants at the Dialogue, however, were more interested in Mattis' thoughts on the Trump administration's approach to the ties and interactions with increasingly nervous regional allies and partners, with Mattis asked at the question and answer session if the American-led global order is in the process of being dismantled.
Theresa May, Jeremy Corbyn to face questions on live TV
In reply, Mr Corbyn said there was a period of silence for "everyone who died in Northern Ireland" at the 1987 event. However, in the past week, her lead has fallen dramatically with Labour taking a huge gain in the opinion polls.
Mattis cited Trump's trip to Brussels last month to meet with North Atlantic Treaty Organisation leaders and the defense secretary himself going to Japan and South Korea within days of taking office as examples of how the United States is still involved on a world stage.