Seoul, South Korea (CNN) -- North and South Korea said their naval forces clashed Tuesday in disputed waters, and each blamed the other for what is the first such violent incident in seven years.
South Korean Rear Adm. Lee Ki Sik said the nation's forces issued three verbal warnings to a ship from the Communist north once it had crossed a demarcation line late Tuesday morning.
The South Koreans then fired a warning shot, but when the North Korean vessel continued southward, the South Koreans opened fire. Lee said the North Koreans returned fire before heading back, their ship damaged in the exchange.
North Korea, however, defended its actions. The patrol boat was on "routine guard," according to a North Korean army report cited by the official Korean Central News Agency (KCNA), and the incident occurred because of "provocation perpetrated by the South Korean forces in the waters of the north side."
"The South Korean military authorities should make an apology to the North side for the armed provocation and take a responsible measure against the recurrence of the similar provocation," said the report.
Lee said there were no South Korean casualties, and the North Koreans report didn't mention any casualties in the clash, which occurred off the Korean peninsula's western coast.
A senior Obama administration official told CNN that South Korea was downplaying the incident, which didn't appear to be deliberately provocative. Another South Korean official told the nation's semi-official Yonhap News Agency that South Korea was not ruling out "the possibility that the clash may have been accidental."