A maritime official says Somali pirates have hijacked a Yemeni cargo ship in the Gulf of Aden.

Andrew Mwangura, of the East African Seafarers Assistance Program, identified the vessel Tuesday as the MV Amani.

It was not immediately clear when the ship was hijacked.

Somali pirates have hijacked nearly 40 ships this year.

In Malaysia Monday, an international association of tanker owners called for a military blockade along the coast of Somalia. NATO Secretary-General Jaap de Hoop Scheffer said the alliance is not considering such a move.

NATO is among the world powers that have sent ships to patrol the waters off Somalia. Somali pirates are wreaking havoc in shipping lanes near the country.

The Somali government, which is threatened by an Islamist insurgency, lacks the power to stop the attacks.

Some information for this report was provided by AFP, AP and Reuters.