Pyongyang, North Korea - North Korea said that it has conducted a missile test for the second time in just a few days, in a bid to expand the country's nuclear strike capability, state media reported on Monday.

The cruise missiles hit their target on an island in the sea between the Korean peninsula and Japan, state-controlled media reported. It was initially unclear how far they flew.

Two "newly developed, submarine-launched strategic cruise missiles" of the type Pulhwasal-3-31 were launched on Sunday under the guidance of North Korean leader Kim Jong-un, state media reported.

Kim's goal to broaden the country's nuclear capability is being carried out as planned, the reports said. The navy's nuclear armament is also accelerating.

South Korea's military recorded the launch of the cruise missiles on Sunday, however, it was unclear whether they were fired from a submarine or possibly from a marine platform.

North Korea claimed to have tested the same weapon for the first time last Wednesday.

In addition to nuclear-capable ballistic missiles, North Korea has also tested cruise missiles, which it describes as strategic, on several occasions in recent years.

The designation as a strategic weapon suggests that North Korea may also have adjusted cruise missiles – which are not banned under the UN sanctions regime – for the deployment of nuclear warheads.