NAIROBI (Reuters) - Pirates seized a Saint Vincent and the Grenadines flagged merchant ship off the coast of the Seychelles on Sunday, the EU naval force said.

A regional maritime body warned other vessels to avoid the area for the next two days as the weather was suitable for more hijackings.

"The ... cargo ship MV Rak Afrikana has been hijacked this morning ... approximately 280 nautical miles west of Seychelles," EUNAVFOR said in a statement.

"The Rak Afrikana has currently stopped due to engine problems."

Andrew Mwangura, head of the East African Seafarers' Assistance Programme, said the ship had a crew of 23 Chinese.

EUNAVFOR said Seychelles' Rak Afrikana Shipping Ltd owned the 7,561-dwt ship.

Gangs have seized dozens of ships in the Indian Ocean and Gulf of Aden over the last few years. Despite international naval patrols, pirate activity is predicted to rise in coming months as the weather improves.

Mwangura said ships should avoid the seas around where the Rak Afrikana was taken for the next two days.

"This area will remain high risk for the next 24-48 hours as weather conditions continue to be conducive to small boat operations," he said in a statement.

Somali pirates have made millions of dollars in ransoms by hijacking ships off their anarchic country's coast and have extended their range using mother ships, sometimes seized vessels, from which to launch attacks with smaller craft.