Somali gunmen hijacked a Cambodian cargo ship, the MV Layla-S, off Berbera after it unloaded at the port in the breakaway northern enclave of Somaliland, a regional maritime official said on Thursday.

"Crew members on board the ill-fated vessel are ... Pakistani, Indian, Sri Lankan, Somali and Syrian nationals," Andrew Mwangura of the Mombasa, Kenya-based East African Seafarers' Assistance Programme said in a statement.

"It is said that the vessel has a link with Syrian and UAE businessmen. We are informed that she was taken by gunmen after discharging her cargo."

The hijacking appeared to have happened on Wednesday, but few other details were immediately available. The seizure came a week after Somali pirates freed a Greek-flagged tanker carrying 2 million barrels of oil for a record ransom.

Somaliland, which declared itself independent in 1991, is proud of its relative stability compared with the south of Somalia, where hardline Islamist rebels control large amounts of territory and are battling a weak Western-backed government.

Worldwide, piracy attacks rose by nearly 40 per cent last year, with Somali gangs accounting for more than half the 406 reported incidents, the International Maritime Bureau says.

Typically, pirates from the failed Horn of Africa state hold the captured ships and crews hostage until ransoms are paid.

The International Chamber of Shipping, which represents 75 per cent of the global seaborne industry, said this month that it felt deepening frustration at the international community's "impotence" in combating growing piracy in the Indian Ocean. – Reuters