SEOUL (Reuters) - North Korea has declared a no-sail zone off its east coast in a sign it could be preparing a missile launch, Yonhap news agency reported on Sunday (Nov 15).

The warning covers all movement of ships from Nov 11 to Dec 7 for an area off the North's central coast, the agency said, quoting an unnamed government source.

"We are observing closely whether North Korea will launch a Scud missile or a new model of ballistic missile because the area under the warning is quite vast," a government source was quoted as saying by Yonhap.

The Scud is a short-range missile initially developed by the Soviet Union.

South Korea's defence ministry declined to confirm whether a no-sail warning had been issued.

The prohibited area is near the eastern port city of Wonsan where leader Kim Jong Un's family compounds are located, according to media reports.

The North has previously declared a no-sail zone without launching a missile. The country is under UN sanctions for its previous ballistic missile launches and nuclear tests.