An unarmed missile capable of sending a nuclear bomb across the world was launched on Wednesday from California amid rising tensions between the United States and North Korea.

The unarmed Minuteman 3 intercontinental ballistic missile blasted off from a silo at 12:02 a.m. from Vandenberg Air Force Base and delivered a single re-entry vehicle to a target approximately 4,200 miles away at Kwajalein Atoll in the Pacific Ocean, the Air Force Global Strike Command said.

The test, which took 10 months to plan, was the latest designed to check the readiness and accuracy of a weapon system that forms part of the US nuclear force.

The US has about 450 such missiles, each capable of traveling about 8,000 miles.It was the second such launch in seven days from the Central California coastal base. Last week’s had been delayed from the fall. Both come at a time when the US has expressed concern about North Korea’s nuclear capability.