TOKYO — Kim Jong Un has presided over a rocket engine test “of historic significance,” North Korean state media said Sunday, a test that coincided with Secretary of State Rex Tillerson’s visit to neighboring China.

The North Korean leader declared “that the whole world will soon witness what eventful significance the great victory won today carries,” the report said, declaring Saturday as the “March 18 revolution” because of the “great leaping forward” in North Korea’s rocket industry.

The Kim regime has a history of making exaggerated claims and belligerent threats that it can’t back up, but the latest boast comes amid heightened tensions in the region.

North Korea has been making steady and observable progress with its missile program, and Tillerson said Friday that that “all options,” including military ones, were on the table to stop it.

The rocket engine that North Korea tested appeared to be powered with liquid fuel, according to Melissa Hanham, an expert at the James Martin Center for Nonproliferation Studies, rather than the solid fuel the regime’s engineers have been working on recently. Liquid fuel rockets are much easier to spot with satellites because they require more outdoor preparation.

“There is nothing about this rocket engine itself that makes me more terrified, but taken as a whole, it’s pretty clear that they are trying to give us proof of their growing missile program,” Hanham said.

Kim said in his New Year’s address in January that North Korea had “entered the final stage of preparation for the test launch of an intercontinental ballistic missile.” This ICBM would be aimed at reaching the United States mainland.

Since then, North Korea has fired a medium-range missile that appeared to show significant technological advances. This month, it launched a barrage of four missiles, three of which landed within Japan’s exclusive economic zone.