The U.S. Air Force successfully test-launched an intercontinental ballistic missile from the California coast early Wednesday.

The unarmed Minuteman 3 missile was launched from Vandenberg Air Force Base, about 130 miles northwest of Los Angeles. It was the fourth such test this year. The most recent was in May.

The Air Force said the test would show the effectiveness, readiness and accuracy of the weapon system.

The test comes amid heightened tensions with North Korea. The reclusive nation launched its second inter-continental ballistic missile in a month Friday, in a further indication that its missiles are now capable of reaching U.S. cities. The U.S. flew two B-1 bombers over South Korea in a show of force in response.

On Tuesday, Secretary of State Rex Tillerson said the U.S. does not seek a regime change in North Korea and would agree to a dialogue if the nation abandons its nuclear weapons program.

“We’re trying to convey to the North Koreans, we are not your enemy,” Tillerson said at a State Department briefing. “We’re not your threat, but you are presenting an unacceptable threat to us, and we have to respond.”

“We would like to sit and have a dialogue with them about the future that will give them the security they seek and the future economic prosperity for North Korea.”