"We will be doing something very rapidly having to do with additional security for our country. You will be seeing that sometime next week," Trump said at a news conference with Japanese Prime Minister Shinzo Abe, without elaborating on what the actions will be.
At times, the press conference appeared to show an administration still finding its feet in the stagecraft of foreign policy. During Abe's opening remarks, Trump did not appear to use an earpiece to listen to a translation. And he almost closed the event before the second scheduled question from the Japanese press.
Significantly, Trump did not get asked by reporters he selected from the Rupert Murdoch-owned New York Post and the Fox Business Network about two other key news stories of the day, including claims that his national security adviser, Michael Flynn, breached protocol by talking to the Russian ambassador to Washington about US sanctions policy before the current administration took office.
There was also no question on Trump's apparent shift on policy toward Beijing after he reaffirmed the "One China" policy after earlier suggesting he would use US relations with Taiwan as a bargaining chip in trade talks with the Chinese government.
Trump began the East Room news conference by renewing US security guarantees to Japan concerning islands in the East China Sea, with which it has a territorial dispute with Beijing.
"We are committed to the security of Japan and all areas under its administrative control," Trump said.
Japan calls the island chain the Senkakus, while China calls them the Diaoyu Islands.
The US recognizes Japanese administration of the islands and says Article 5 of the US-Japan Security Treaty applies to them. But there had been some doubt over Trump's position on the issue -- at least until Defense Secretary James Mattis renewed the guarantee last week.
Trump effectively recommitted the United States to standard US policy on Northeast Asia despite casting doubt on the utility of the alliance between the United States and Japan during his election campaign.
"We will work together to promote our shared interests, of which we have many in the region, including freedom ... of navigation and defending against the North Korean missile and nuclear threat, both of which I consider a very, very high priority," Trump said.
The President made no mention of his demands for Japan to pay the United States more for its security guarantees and the presence of Japanese soil of thousands of US troops. And his prior criticism of Japanese trade practices was also absent.
But he did hint at some evolution in the relationship, noting that the US and Japan were committed to invest "very heavily" in defense and defensive military capabilities and added that the trading relationship needed to be "free, fair and reciprocal."
Trump and Abe, who held Oval Office talks and had lunch together in the State Dining Room, were later to fly to Florida with their wives, where they will stay at Trump's luxury Mar-a-Lago club and play golf on Saturday.