Two North Korean missile launches in recent weeks were test firings of a powerful new long-range ICBM, the US has said and warned that a full-range test could soon follow.

The tests were of a missile reportedly larger than an ICBM North Korea launched in 2017 that was assessed to be capable of reaching the United States.

American missile defence and reconnaissance forces in the Pacific have been placed in a state of "enhanced readiness" in preparation for a full-range test, a senior administration official said on Thursday.

The official outlined the US intelligence assessment of the recent launches on the condition of anonymity. North Korea has claimed the March 4 and February 26 launches were merely to test cameras to be installed on a future spy satellite.

South Korea said that North Korea's use of new intercontinental ballistic missiles in its recent two weapons tests could possibly be a disguise for launching a space vehicle.

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US sanctions 

Multiple UN Security Council resolutions prohibit North Korea from firing ICBMs, and the US will announce a new round of sanctions on Friday meant to make it more difficult for the country to access technology needed for its weapons programmes, the official said.

The 2017 launch was part of a series of tests that prompted then-president Donald Trump to threaten North Korea's leaders with "fire and fury" and brought the two countries to the brink of more serious conflict.

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 that is larger than any of the North’s known ICBMs. 

The US official who commented on Thursday did not estimate the maximum range.

Last week's launch was North Korea's ninth round of weapons tests already this year as it uses a break in diplomacy to expand its military capabilities while attempting to pressure the Biden administration for concessions.

READ MORE:North Korea conducts ‘significant’ test for developing spy satellite

Kim for expanding ICBM launch site

Earlier on Friday, North Korean leader Kim Jong-un has called for expanding its site for launching intercontinental ballistic missiles (ICBMs) into an "ultramodern advanced base" in order to become a space power, state media KCNA reported.

Kim inspected the base and ordered modernising and expanding it to ensure that "various rockets could be launched to carry multi-purpose satellites, including a military reconnaissance satellite."

READ MORE: North Korea claims new test of spy satellite component