WASHINGTON- Two US B-1B strategic bombers and two Japanese F-15 fighter jets conducted a joint night exercise over the East China Sea on Thursday, the US Pacific Air Forces said.

It was the first night-time drill involving a US B-1B bomber and a fighter jet from the Japanese Air Self-Defense Force.

The move was apparently aimed at reining in North Korea 's provocations after Pyongyang fired what it claimed to be an intercontinental ballistic missile on Tuesday.

According to the ASDF, the F-15 jets from its Naha base in Okinawa Prefecture , southernmost Japan , joined the B-1B bombers over the East China Sea after the US aircraft flew from Andersen Air Force Base in Guam . They made formation flights and other exercises.

"This is a clear demonstration of our ability to conduct seamless operations with all of our allies," the US Pacific Air Forces said in a statement.

After the drill, the B-1Bs proceeded to the South China Sea, where China has claims, before returning to Guam .

"The recent mission demonstrates how the United States will continue to exercise the rights of freedom of navigation anywhere international law allows," the US Pacific Air Forces said, in an apparent warning against China's maritime assertiveness.

The mission was apparently part of a campaign by the administration of US President Donald Trump to urge China to increase pressure on North Korea to abandon its nuclear and missile programs. (Jiji Press)