The UN Security Council on Thursday condemned North Korea's latest ballistic missile tests and agreed to quickly consult on an appropriate response, its rotating president said.

"Security Council members condemn this launch as a violation of Security Council resolutions," Luxembourg's ambassador Sylvie Lucas told reporters after a closed-door debate of less than an hour.

The condemnation did not amount to a formal statement from the 15-member council. Instead Lucas said members had requested that she read out the remarks as agreed by all participants.

"Members of the Security Council agree to consult on an appropriate response," she said.

In response to questions, she said panelists agreed this response "should be given quickly."

The UN discussions, which included a report from the deputy secretary general for political affairs, Jeffrey Feltman, had been requested by the United States.

Pyongyang has carried out a series of rocket and short-range missile launches in recent weeks, sparking condemnation from Seoul and Washington.

On Wednesday, it upped the ante by test-firing two mid-range ballistic missiles capable of striking Japan.

The move came in response to President Barack Obama's hosting of a Japan-South Korea summit in The Hague.

The tests go against UN resolutions barring Pyongyang from any nuclear or ballistic activity.

Diplomats said the United States urged the council to condemn the missile tests, calling for a swift and firm response.

Close allies Britain and France also demanded that the council react and send a clear warning to North Korea.

But China, a traditional ally of North Korea, was more prudent, arguing that reaction should be proportionate to Pyongyang's actions.

For Beijing, the priority should be to resume talks between the two Koreas, China, Japan, Russia and the United States, which broke down in late 2008.

The negotiations had sought to put a stop to North Korea's nuclear program in exchange for economic assistance.

South Korea's ambassador to the United Nations, Oh Joon, said North Korea needed to be given a warning in clear terms.

"From South Korea's perspective we want North Korea to stop their provocations immediately and to stop slandering and to come back to the dialogue with us," he told reporters.

Earlier on Thursday, a South Korean naval ship fired warning shots and seized a North Korean fishing boat intruding across the disputed Yellow Sea border, officials said.

Nearly 15,000 South Korean and US troops have kicked off a 12-day amphibious landing drill, the largest for two decades.

The joint exercise taking place off the country's southeast coast will last until April 7 and involve around 10,000 US troops.

North Korea views such exercises as provocative rehearsals for invasion and there is a risk they could further fuel already simmering military tensions.