North Korea announced Sunday that it had conducted an underground test of what may be the country's most powerful nuclear device.
"We have many military options, and the president wanted to be briefed on each one of them", said Defense Sec.
"Our commitment among the allies are ironclad", Mr Mattis said.
When asked earlier today if he would consider attacking North Korea, Trump said: 'We'll see'.
North Korea conducted a test of a hydrogen bomb on Sunday that can fit on an intercontinental ballistic missile. A top South Korean military officer said in a statement. The warning arrived after the Kim Jong-un regime reportedly tested a hydrogen bomb.
He also appears to show increasing frustration with South Korea for failing to get North Korea to stop the nuclear testing.
Even if that's a possibility, analysts say the United States is in no position right now to wage the kind of military campaign that could bring battlefield success on the Korean Peninsula.
The Chinese Foreign Ministry released a statement urging North Korea "to face up to the firm will of the global community on the denuclearization of the peninsula. stop taking wrong actions that exacerbate the situation and are not in its own interest, and return to the track of resolving the issue through dialogue".
Paris Saint-Germain set for FFP investigation after Neymar, Mbappe deals
Mbappe burst onto the scene in the second half of last season and scored 15 goals in 29 appearances in Monaco's run to the French title.
Trump's threat to halt all economic ties with any country that does business with North Korea amounts to his biggest trade salvo to date and would be almost impossible to pull off without having enormous implications for the US economy.
His words echo those of President Trump, who took to Twitter following Pyongyang's announcement to state that appeasement would not work with North Korea.
Chinese President Xi Jinping and Russian President Vladimir Putin agreed on Sunday to "appropriately deal with" the latest nuclear test by North Korea, state news agency Xinhua said.
South Korean President Moon Jae-in has ordered the "strongest" response to the test, which was reported to have been a 6.3 magnitude seismic event taking place at 1200 Pyongyang time.
"If the United States wants to rein-in the North Korean nuclear weapon and missile programs, it needs to convince Kim Jong-un that the things he cares about (mainly regime survival) are jeopardized by his bad behavior-only then is he likely to be prepared to compromise".
It has always been accepted that North Korea has intercontinental ballistic missiles (ICBMs) capable of reaching the mainland of the United States.
Washington is becoming increasingly frustrated with Beijing's approach to North Korea, with some officials advocating that China imposes an oil embargo on the rogue state.