South Korea said it has scrambled F-16 fighter jets and returned fire after North Korea shot dozens of rounds of artillery on to a populated South Korean island near the countries’ western border.
South Korea’s YTN television said two people were injured and several houses were on fire after shells fell on Yeonpyeong island.
Yonhap news agency, quoting a military official, said four soldiers are wounded.
YTN said between 1,200 and 1,300 people lived in the island and TV pictures showed black and white smoke rising.
The firing comes amid tension over North Korea’s claim that it has a new uranium enrichment facility.
The countries’ western maritime boundary has long been a flashpoint between the two Koreas.
The North does not recognise the border that was unilaterally drawn by the United Nations at the close of the 1950-53 Korean War.
North and South Korea have fought three bloody skirmishes near the maritime border in recent years, most recently in November 2009.