SEOUL, South Korea — The United States flew two supersonic bombers over the Korean Peninsula on Sunday in a show of force against North Korea following the country’s latest intercontinental ballistic missile test. The U.S. also said it conducted a successful test of a missile defense system located in Alaska.

The B-1 bombers were escorted by South Korean fighter jets as they performed a low-pass over an air base near the South Korean capital of Seoul before returning to Andersen Air Force Base in Guam, the U.S. Pacific Air Forces said in a statement.

It said the mission was a response to North Korea’s two ICBM tests this month. Analysts say flight data from the North’s second test, conducted Friday night, showed that a broader part of the mainland United States, including Los Angeles and Chicago, is now in range of Pyongyang’s weapons.

Vice President Mike Pence said Sunday in Estonia that the U.S. and its allies plan to increase pressure on North Korea. “The continued provocations by the rogue regime in North Korea are unacceptable and the United States of America is going to continue to marshal the support of nations across the region and across the world to further isolate North Korea economically and diplomatically,” Pence said.

“But the era of strategic patience is over. The president of the United States is leading a coalition of nations to bring pressure to bear until that time that North Korea will permanently abandon its nuclear and ballistic missile program.”

Gen. Terrence J. O’Shaughnessy, Pacific Air Forces commander, called North Korea “the most urgent threat to regional stability.”

U.S. Ambassador to the United Nations Nikki Haley said in a statement: “The time for talk is over.” She denied reports that Washington would seek an emergency session of the U.N. Security Council. Haley said a weak resolution would show North Korean leader Kim Jong Un that “the international community is unwilling to challenge him.”

Sen. Dianne Feinstein, D-Calif., told CBS’ “Face the Nation” that North Korea’s latest test presents danger to the United States. “I’ve spent time on the intelligence and at the briefings, and done as much reading as I possibly could,” said Feinstein, a member of the Senate Intelligence Committee. “And I’m convinced that North Korea has never moved at the speed that this leader has to develop an ICBM.”

Feinstein said the situation shows the danger of isolating a country.

“I think the only solution is a diplomatic one,” she said. “I’m very disappointed in China’s response, that it has not been firmer or more helpful.”

The U.S. Missile Defense Agency said a Terminal High Altitude Area Defense, or THAAD, system located in Alaska was successfully tested on Saturday night. It said a medium-range ballistic missile was air-launched over the Pacific and that the THAAD system intercepted it.