June 8 (Bloomberg) -- North Korea has designated an area off its northeastern coast a no-travel zone from 8 a.m. to 8 p.m. from June 10 to June 30, Japanese Chief Cabinet Secretary Takeo Kawamura said today. Japan’s coast guard picked up the warning from North Korean authorities yesterday, Kawamura told reporters in Tokyo.

“We do not know the reason why North Korea has set up the no-navigation zone,” he said. “We cannot rule out the possibility of North Korea launching missiles including ballistic ones.”

Tensions are rising after North detonated a nuclear device last month, said the 1953 armistice ending the Korean War no longer applies and test-launched several missiles in a show of defiance. South Korea has deployed a warship to its maritime boarder with the North and vowed last week to send F-15K fighter jets in the event of a clash.

To contact the reporter on this story: 広川高史 in Tokyo at thirokawa@bloomberg.net

Last Updated: June 7, 2009 23:00 EDT