JOHANNESBURG (AP) — Pirates off the coast of Nigeria and Cameroon attacked a ship and kidnapped three sailors, including two Russians, in the latest assault on shippers in the increasingly dangerous waters of the Gulf of Guinea, officials said Friday.

A statement from Carisbrooke Shipping Ltd. of the United Kingdom said pirates boarded the MV Esther C late Thursday night. The company said the pirates stole the sailors' personal belongings before leaving with the three sailors.

The remaining crew of the MV Esther C, a U.K.-flagged ship, sailed away from the site of the attack, the company said.

"The safety and well-being of these seafarers is the company's absolute priority and all possible steps to secure their return are being taken," the company's statement read.

Russia's Foreign Ministry said Friday that two of the sailors were Russian. A spokesman for Carisbrooke Shipping declined to identify the nationality of the third sailor taken hostage.

The attack Thursday night comes amid a series of escalating assaults in the Gulf of Guinea, which follows the African continent's southward curve from Liberia to Gabon.

Piracy in the Gulf of Guinea has escalated from low-level armed robberies to hijackings and cargo thefts. Last year, London-based Lloyd's Market Association — an umbrella group of insurers — listed Nigeria, neighboring Benin and nearby waters in the same risk category as Somalia, where two decades of war and anarchy allowed piracy to flourish. But as piracy has dropped in recent months off Somalia's coast, it's only risen in the Gulf of Guinea.

Pirates in West Africa also have been more willing to use violence in their robberies, as they often target the cargo, not the crew for ransom as is the case off Somalia. Experts say many of the pirates come from Nigeria, where corrupt law enforcement allows criminality to thrive and there's a bustling black market for stolen crude oil.

The attacks also have begun to stretch beyond the waters immediately near Nigeria. On Sunday, a gang of pirates seized control of a French-owned oil tanker off Ivory Coast, kidnapping the 17 sailors on board. Pirates released the ship and its sailors a few days later after likely stealing the diesel fuel it had on board.

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Jon Gambrell can be reached at www.twitter.com/jongambrellAP .