The Pentagon on Thursday flight-tested a missile which had been banned under a treaty that the United States and Russia abandoned last summer.

The Pentagon has however declined to disclose specifics about the prototype missile configured to be armed with a non-nuclear warhead. It only said that the missile was launched from a static launch stand at Vandenberg Air Force Base in California.

It added the missile landed in the open Pacific Ocean. This is even as the United States Defense Department said the ballistic missile flew more than 500 kilometers.

The test comes amid growing uncertainty about the future of arms control. The last remaining treaty limitation on US and Russian nuclear weapons, the New START treaty of 2010 is scheduled to expire in February 2021.

That treaty can be extended for as long as five years without requiring a renegotiation of its main terms and the Trump administration has indicated little interest in doing so.

Under the 1987 Intermediate-range Nuclear Forces (INF) treaty, land-based cruise and ballistic missiles with a range between 500 kilometers and 5,500 kilometers were prohibited.

The Trump administration chose to abandon the INF treaty, saying that while it had adhered to the treaty’s limitations, Russia had violated it by deploying a non-compliant cruise missile aimed at US allies in Europe.

Shortly after exiting the treaty in August, the Pentagon flight-tested an INF-range cruise missile.