South Korea has reportedly ordered civilians on the border island of Yeonpyeong to move to shelters after North Korea fired 200 artillery shells into the sea near the island, local news media said on Friday.

“We announced the evacuation after receiving a call from a military unit saying it was carrying out a maritime strike on Yeongpyeong Island as it has a situation with a North Korean provocation,” an official told Yonhap News. The emergency evacuation order was issued at 12:02 p.m. and 12:30 p.m. local time on Friday, the report said.

“The North Korean military fired more than 200 rounds from around 9:00 to 11:00 today in the area of ​​Cape Jangsan, north of Baengnyeong Island, and Cape Sansan, north of Yeonpyeong Island,” South Korea’s Joint Chiefs of Staff said, according to NBC News. No injuries have been reported so far.

In response, the South Korean marine corps requested the evacuation of citizens of Yeonpyeong and scheduled a “maritime shooting exercise” for the afternoon, Chosun Ilbo reported, citing an official from the Yeonpyeong township office.

The official added that most residents have gone to the shelters, and that the end time for the evacuation exercise not yet been determined.

The Chosun Ilbo added: “It is known that the Marine Corps’ maritime shooting training was a response to this,” referring the to North Korean firing.

Yeonpyeong Island is close to what is known as the “Northern Limit Line,” the de facto maritime border that separates the two Koreas. None of the shells fired on Friday crossed the NLL, Reuters said.

In a major escalation of tensions in November 2010, the island was bombarded by North Korean artillery, killing two South Korean marines and two civilians. At least 18 people were injured at that time, and more than 100 buildings damaged.

At the time, then United Nations secretary general Ban Ki-moon called it one of the “gravest incidents” since the Korean War.

North Korea and South Korea are formally still at war, as the Korean War in 1953 ended with an armistice and not a formal peace treaty.