TOKYO, April 1 (AFP) - Japan's government on Friday (Apr 1) approved fresh sanctions against North Korea over its recent test-firing of an intercontinental ballistic missile, following Washington's calls for tougher international punishment for the nuclear-armed state.

Japan already has bans on trade and vessel entries as part of unilateral sanctions against Pyongyang, but said on Friday it would "designate four groups and nine individuals involved in nuclear and missile development".

The entities and individuals would be "subject to an asset freeze," top government spokesman Hirokazu Matsuno told reporters.

Japan's move comes after Washington called for a "resolution to update and strengthen the sanctions regime" against Pyongyang at the UN Security Council last week in the wake of the isolated regime's first ICBM launch since 2017.

North Korea said the launch was a successful test of a Hwasong-17 missile - a long-range ICBM that analysts say may be capable of carrying multiple warheads - which it first unveiled at a military parade in 2020.

But South Korea's defence ministry told AFP that Seoul and Washington have now concluded that the launch was actually of a Hwasong-15, an ICBM that Pyongyang test-fired in 2017.

Still, experts say the launch indicated significant progress.

It also alarmed Japan, particularly as the missile landed inside its exclusive economic zone.