McMaster said various U.S. military and intelligence agencies are working on providing options to "have them ready" for Trump "if this pattern of destabilizing behavior continues".
While not publicly defining its plans, the White House has said that all options are on the table to prevent North Korea from acquiring the ability to strike the US with a nuclear weapon. He said the USA and its allies would deal with the situation "through peaceable means or ultimately by whatever means are necessary". -South Korea military drills that began last month.
Trump acknowledged on Sunday that the softer line he had taken on China's management of its currency was linked to its help on North Korea.
After a two-month policy review, officials settled on a policy dubbed "maximum pressure and engagement", US officials said Friday.
The Global Times, an English-language Chinese newspaper that does not necessarily reflect official policy, recommended that Beijing convey a clear message to Pyongyang: that if it conducts a sixth nuclear test, the Chinese government would support stiffer United Nations sanctions to cut off "the vast majority" of its oil supplies to North Korea.
Pence will be tasked with explaining the policy in meetings with leaders in South Korea and Japan during the trip, which will also include stops in Indonesia and Australia.
U.S. Vice President Mike Pence will travel to South Korea on Sunday in what his aides said was a sign of the U.S. commitment to its ally in the face of rising tensions over North Korea's nuclear program.
The U.S. last week acted unilaterally in ordering a cruise missile strike on Syria and has sent what Trump called an "armada" to the waters off the Korean Peninsula. The adviser spoke on condition of anonymity to discuss the administration's initial understanding of the launch.
A new type of Korean People's Army tracked TEL, or transporter erector launcher, made its first appearance at the weekend. She advised patience with China on the issue.
On Tuesday, Pence will kick off economic talks with Japan requested by Trump and Prime Minister Shinzo Abe.
The US Pacific Command said the missile "blew up nearly immediately", adding the type of missile was being analysed.
Pence told reporters that the North Korean people and military "should not mistake the resolve of the United States of America to stand with our allies", calling the alliance "iron-clad".
While interest in North Korea spikes immediately after a missile launch, within hours internet search traffic is again dominated by TV comedy shows, taxes and real estate. He suggested plans to deploy a US missile defense system in South Korea were damaging its relations with China. A spokesman from the DPRK Ministry of Foreign Affairs said the "sudden" dispatch of the carrier task group to the peninsula is evidence that Washington's "reckless moves of invading the DPRK have reached a serious phase of its scenario".
Outside experts say the North could conduct its sixth nuclear test at virtually anytime.
United States officials said the missile in today's test exploded on launch but they don't know exactly what type of weapon it was.
"It's there to prevent rockets slamming from the North Koreans", an American official said while previewing Pence's trip.
"Why would I call China a currency manipulator when they are working with us on the North Korean problem?"
"We will see what happens!" Trump tweeted on Sunday.
US President Donald Trump held a summit with Chinese President Xi Jinping earlier this month, and has praised China's turning back of North Korean coal ships as a "big step" forward in the effort to enlist Chinese pressure on Pyongyang.
Some 28,500 United States troops are stationed in the South. I mean, North Korea is very vulnerable to pressure from the Chinese.
On State of the Union, Sen.
Asked about North Korea this past week, he told reporters: "North Korea is a problem". Mr Trump said on Twitter.
"China is the key", Senator John McCain, chairman of the Armed Services Committee, said on Sunday on NBC. "The North Koreans know they may fail, but they improve their capabilities each time".
Trump's shifts in foreign policy were a focal point in some of the interviews.
CNN's Abigail Crutchfield and Kevin Bohn and The Associated Press contributed reporting.