U.S. Secretary of State Rex Tillerson said on Thursday that the escalating threat from North Korea's nuclear program showed a clear need for a "new approach," although he stopped short of detailing what steps the Trump administration will pursue.

Tillerson was speaking at a news conference following talks with Japanese Foreign Minister Fumio Kishida in Tokyo, the start of his first trip to Asia as secretary of state. It was the first time Tillerson has taken questions from the media since he took office in early February.

Two decades of diplomatic and other efforts, including aid given to North Korea by the United States, had failed to achieve the goal of denuclearizing Pyongyang, Tillerson said.

"So we have 20 years of failed approach," Tillerson said. "That includes a period where the United States has provided $1.35 billion in assistance to North Korea as an encouragement to take a different pathway."

He added: "In the face of this ever-escalating threat, it is clear that a different approach is required. Part of the purpose of my visit to the region is to exchange views on a new approach."

Japan is seeking clues to Washington's policies on a volatile North Korea and a rising China while hoping to steer clear of trade rows during Tillerson's visit.

U.S. President Donald Trump made it a hallmark of his presidential campaign to call on U.S. allies, including Japan, to pay more for hosting U.S. forces and other elements of U.S. protection.

During the joint news conference with Kishida, Tillerson said that the United States welcomes an increased Japanese commitment to its "roles and responsibilities" within its alliance with the United States.