North Korea fires about a dozen missiles, Seoul says

North Korea fired around a dozen short-range ballistic missiles from the Wonsan area toward the East Sea on Thursday, South Korea's Joint Chiefs of Staff said.

The South Korean military said the missiles flew about 250 kilometres. It said South Korea and the United States were conducting a detailed analysis of their exact specifications, and that Seoul had increased surveillance for possible additional launches.

The Japan Coast Guard earlier urged ships in the area to be vigilant.

South Korea's National Security Office said the launches violated UN Security Council resolutions and called them serious acts that did not help manage the current situation.

The launches came less than a week after South Korea proposed military talks with North Korea to confirm the location of their border and discuss restoring communication channels. Pyongyang has not responded to that proposal.

Tensions have risen after a landmine explosion along the heavily fortified border wounded three South Korean soldiers. A joint Seoul-UN investigation concluded this month that North Korea planted the mines more than a year ago. Seoul demanded an apology, while North Korea dismissed the accusation.

Lim Eul-chul, a professor at Kyungnam University, told AFP the launches should be seen as a high-level show of force and a political warning to Seoul.