The Biden administration described the tests as a "serious escalation" after the US scrutinised two recent missile launches, which Pyongyang said were intended to put satellites in space.

North Korea claimed the 4 March and 26 February launches were to test cameras to be installed on a future spy satellite.

A senior Biden administration official said: "The US government has concluded that the Democratic People's Republic of Korea performed two ballistic missile tests involving new intercontinental ballistic missile system."

"This confirms the South Korean government report about the tests. This is a serious escalation by the DPRK.

"Unlike past tests, DPRK tried to hide these escalatory tests. Tomorrow the treasury will announce new actions against DPRK, intended to show the DPRK these tests have consequences."

North Korea could run full-range tests soon

The Biden administration warned that a full-range test could soon follow, and the recent tests were of a missile reportedly larger than an ICBM North Korea launched in 2017.

ICBMs alarm western countries as they have the potential to carry a nuclear warhead vast distances, and to reach countries like the US and those in Europe.

The 2017 tests promoted then US President Donald Trump to threaten North Korean leaders with "fire and fury".

The intelligence from the US follows reports last week from South Korea, which said the 4 March missile was fired near Pyongyang and landed between the Korean peninsula and Japan.

North Korea is prohibited from firing ICBMs by several United Nations Security Council resolutions.

The new missile was first revealed to the public in 2020 during celebrations marking the 75th birthday of North Korea's Communist Party in Pyongyang.

It appeared to be an intercontinental ballistic missile, larger than any of North Korea's known ICBMs.

The US official added the American intelligence assessment was generated and shared in consultation with allies in the region, including South Korea and Japan.