SEOUL, South Korea -- The new U.S. administration has yet to unveil its plans for a new strategy toward the Asia-Pacific, but the "pivot" or "rebalance" -- as former President Barack Obama's policy of deeper engagement was known -- has been officially put to rest.

A senior State Department official rejected the terms while acknowledging there's nothing yet to replace them.

The comments came on the eve of Secretary of State Rex Tillerson's first trip to Asia in his new role, with stops planned in Japan, South Korea and China.

"On the issue of pivot, rebalance, et cetera, I mean, that was a word that was used to describe the Asia policy in the last administration," said Susan Thornton, acting assistant secretary of state for East Asian and Pacific affairs.

During a press briefing in Washington on Monday, she outlined general principles as part of a preview of Tillerson's Asia trip.

Those included remaining "engaged and active in Asia," working on fair trade and free trade issues and of course addressing the growing threat from North Korea, which has test-fired two ballistic missiles in defiance of economic sanctions since Trump took office on Jan. 20.

That followed an unprecedented spate of activity last year that included two nuclear tests and two dozen missile launches.

"We're working on regional security challenges such as North Korea, and continue to press for a ... constructive, peaceful, stable order in Asia," Thornton said. "Whether there will be a kind of a bumper sticker to put on that at some point ... like I said it's early days so I think it's early to say."

The "pivot" or "rebalance" to Asia were terms used to describe Obama's foreign policy aimed at boosting U.S. defense, diplomatic and economic ties with the Asia-Pacific region. It was part of his effort to shift military and economic focus from the Middle East, but it was heavily challenged by continued war in Iraq and Syria as well as disputes with China and North Korea's defiance.

Tillerson's trip, which begins Wednesday in Japan, will be closely watched for clues about President Donald Trump's Asia policy.

The Trump administration has promised to maintain Washington's commitment to longstanding alliances with Japan and South Korea, where the U.S. maintains 50,000 and 28,500 servicemembers, respectively.

But the president also has stressed the need to put American jobs and needs first.

Meanwhile, China is smarting over plans to deploy an advanced U.S. missile defense system in South Korea despite Beijing's objections.

John Delury, an international relations professor at Yonsei University in Seoul, said the semantics underscore the uncertainty over Trump's strategy.

"Strategic drift is not healthy for the region," he said. "If it's true that they really don't have a strategy – that the pivot's been repealed but there's nothing to replace it -- then Tillerson's got his work cut out for him."

Delury also noted that a centerpiece of the "pivot" was negotiations for the Trans-Pacific Partnership trade deal, which Trump pulled out of in one of his first acts in office.

Thornton, meanwhile, played down expectations for major announcements during Tillerson's trip, saying it will be focused on establishing good lines of communication and trying to develop a "constructive and results-based relationship with China." She said there were no plans to announce new sanctions against North Korea.

Scott Snyder, director of the U.S.-Korea policy program at the New York-based Council on Foreign Relations, said he wasn't surprised by the rejection of the Obama-era terminology and stressed it's too early to judge the new administration's policies.

"Trump's administration will describe its policies using its own language," he said.