Image copyright Twitter/@PACAF Image caption Two US B-1B bombers took part in the joint drill with Japan

The US has flown two bombers over East Asian waters, as tensions continue to run high in the region.

The B-1B Lancers took part in joint military drills with Japan in the East China Sea, the US Air Force said in a statement.

They then flew over the highly contentious South China Sea.

On Tuesday, North Korea test-fired a long-range missile some believe could reach Alaska, sparking concerns over its weapons capabilities.

A statement by the US Pacific Air Forces said the flights with Japan "demonstrate the solidarity between Japan and the US to defend against provocative and destabilising actions in the Pacific theatre".

Tuesday's launch of an intercontinental ballistic missile (ICBM) by North Korea sparked a warning from the US that it would use military force "if we must".

The US has been firing missiles into South Korean waters in joint ballistic missile drills in response to the missile test.

Media playback is unsupported on your device Media caption America's UN ambassador Nikki Haley says the US is prepared to defend itself and its allies

Japan, which sent two F-15s for the joint drill, also has competing claims with China in the East China Sea.

After the joint flypast, which took place at night, the two bombers headed to the South China Sea to "exercise the rights of freedom of navigation", said the US statement.

They then returned to the US airbase in Guam.

China claims sovereignty over almost all of the South China Sea, which the US has challenged.

Last weekend a US warship sailed near one island sparking an angry response from Beijing.

What is Freedom of Navigation?

The US Freedom of Navigation programme challenges "excessive claims" to the world's oceans and airspace.

It was developed to promote international adherence to the UN Convention on the Law of the Sea.