North Korea launched at least 25 missiles off its east and west coasts on Wednesday, one of which flew near South Korean waters and triggered an air-raid alert on a populated island, where people took cover. It was the first time the North had fired that many missiles in a single day.

South Korea responded by firing missiles from fighter jets into waters near the North’s territory. The exchange marked the first time missiles had been launched across the Koreas' maritime border, the South’s defence ministry said, though all of them fell into international waters.

One of the North’s missiles landed 103 miles northwest of Ulleung, an island off South Korea’s east coast with a population of about 9,000, prompting the military to issue an air-raid alert there. Lieutenant General Kang Shin Chul, the South Korean military’s chief director of operations, called the launch “a highly unusual and intolerable act”.

“The siren started blaring at 8:55 am (local time) and we got a message from our government computer system saying that this is ‘a real-life situation’”, not a mock drill, said Chung Young-hwan, a local official on Ulleung. “We took refuge at an underground shelter for three or four minutes before coming out again.”

Chung said that the siren was triggered across the island but residents were not immediately told the reason for it. “We knew that it was a North Korean missile when we saw news flashes,” he said.

The South’s military later said that its fighter jets had fired three missiles into international waters not far from the North’s own waters.

New York Times News Service