North Korea has recently declared a no-navigation zone in the waters near its eastern coastal city of Wonsan, a possible indication that the country could test-launch a missile in the area, sources said Sunday.

"North Korea declared the no-sail zone in the East Sea area near Wonsan, Gangwon Province, effective from Nov. 11 to the 7th of next month," a government source said. "It is a vast area of the sea, so we are closely watching whether the North will launch a Scud or a new type of ballistic missile."

Other sources said the test launch could involve a new type of missile that separates into several sub-missiles at a high altitude, a missile technology owned by the North.

"It is also possible they could fire a submarine-launched ballistic missile (SLBM) during the no-navigation period," another source said.

Recent satellite images showed the North is preparing for another test of a SLBM, having installed a vertical launch tube at its Sinpo dockyard on the east coast.

Since its land mine and shelling provocations in August, the North has declared no-sail zones in the East Sea each month and deployed ship-to-ship missiles and 300-millimeter multiple rocket launchers on the shore, although it did not go ahead with any firing, the sources added. (Yonhap)