FACTBOX-Ships held by Somali pirates

(Reuters) - Somali pirates seized four ships in the Gulf of Aden on the same day the United Nations Security Council authorised countries to pursue the gunmen on land.

Andrew Mwangura of the Kenyan-based East African Seafarers Assistance programme said on Wednesday that 19 ships and nearly 400 crew were being held in pirate hideouts along the Somali coast.

Below are some of the ships believed to be held:

FAINA: Seized September 24. The ship was carrying 33 T-72 tanks, grenade launchers and ammunition destined for Kenya's Mombasa port. Pirates have demanded $20 million (12.9 million pounds) in ransom.

AFRICAN SANDERLING: Seized October 15. The Panama-flagged, Japanese-operated, and Korea-owned bulk carrier has 21 Filipino crew aboard.

STOLT STRENGTH: Seized November 10. The chemical tanker had 23 Filipino crew aboard. It was carrying 23,818 tonnes of oil products.

THE KARAGOL: Seized November 12. The Turkish ship with 14 crew was hijacked off Yemen. It was transporting more than 4,000 tonnes of chemicals to the port of Mumbai.

TIANYU 8: Seized November 13/14. The Chinese fishing boat was reported seized off Kenya. The crew included 15 Chinese, one Taiwanese, one Japanese, three Filipinos and four Vietnamese.

CHEMSTAR VENUS: Seized November 15. The tanker was travelling from Dumai, Indonesia to the Ukraine. It had 18 Filipino and five South Korean crew.