COTONOU (Reuters) - Nearly two dozen West and Central African nations have pledged to combat the growing threat of piracy and maritime crime in their coastal waters.

The two regions border the oil-rich Gulf of Guinea, which is threatening to overtake the waters off Somalia as the world's most dangerous seas for piracy.

Maritime attacks have become increasingly violent as criminal gangs, exploiting governments' inability to police their coastlines, venture further afield from their traditional home waters off Nigeria.

"The ministers are worried by the serious threats posed by piracy, armed robbery and other illegal maritime activities in the waters of Central Africa and West Africa," a statement released after the meeting of foreign and defense ministers in Benin late on Tuesday said.

The ministers called for governments to arrest and prosecute suspected pirates and seize any vessels believed to have been used in acts of piracy. The document also called upon ship owners to "take steps to protect against pirates".

The agreement requires approval of regional heads of state.

Ivory Coast recorded the first in a series of hijackings targeting tankers carrying refined petroleum products in October. The ships and their crews were all released but their cargoes were stolen.

There were at least five attacks last month on ships off Nigeria, which has stepped up anti-piracy operations in its waters. Three of the incidents involved the kidnappings of foreign crew members from cargo ships.

(Reporting Samuel Elijah; Writing by Joe Bavier; Editing by Michael Roddy)