Kim "stressed the need to continue making miraculous achievements in bolstering up the nuclear force one after another in this historic year," the [North] Korean Central News Agency said Tuesday.

North Korean leader Kim Jong-un on Monday called for continued nuclear weapons development after watching three ballistic missiles being fired into the East Sea.

The missiles that were fired Monday seem to be an improved version of the Rodong with a slightly differently shaped warhead.

"They had warheads that looked like cones," a military source here said.

The North Korean media published images showing that the three missiles were fired simultaneously.

The missiles were fired as world leaders met for the G20 summit in Hangzhou, China and flew about 1,000 km before dropping into the sea, apparently in a bid for attention just after the leaders of China and South Korea sat down face to face.

Meanwhile, the UN Security Council in an emergency meeting on Tuesday discussed a response to the latest missile launch.

The launch came only 10 days after a UNSC press statement condemning the North's frantic missile volleys over the past months.