The United States warned Monday that piracy and armed robbery are increasing at an alarming rate in the Gulf of Guinea, pointing to reports by industry experts of at least 32 attacks off the coast of Nigeria alone so far this year.

US Ambassador Michele Sison singled out two pirate attacks off the Nigerian coast on April 11 that led to the apparent kidnapping of a total of eight crew members including the captain of one vessel, a Turkish cargo ship.

She told a UN Security Council meeting that "the economic consequences for the people of the region are devastating," pointing to a report by the London think-tank Chatham House saying as much as 400,000 barrels of crude oil are stolen every day in the Gulf of Guinea.

"By some estimates, Nigeria is losing about US$1.5 billion a month due to piracy, armed robbery at sea, smuggling and fuel supply fraud," Sison said.

She said ineffective government operations, weak rule of law and inadequate maritime law enforcement all contributed to the increase in piracy in the Gulf of Guinea, a major route for oil supplies shipped around the world.

The Security Council adopted a presidential statement calling for the underlying causes to be addressed and expressing concern at the number of incidents and level of violence of acts of piracy and armed robbery in the Gulf of Guinea since 2014. It stressed that coordinated regional efforts are key to countering piracy and thefts off Africa's west coast and urged new measures to prevent money generated from pirates and robbers "from contributing to the financing of terrorism."

Sison warned that without action by Africa and local governments to tackle maritime security challenges, "there is little reason to believe that attacks in the Gulf of Guinea will decline."

Senegal's UN Ambassador Fode Seck, whose country co-sponsored the meeting along with Angola and China, said "the scope of maritime crime in the Gulf of Guinea has broadened its scope and is no longer limited just to the oil sector," but also robbery, illicit fishing, trafficking in migrants, human beings, drugs, weapons, generic medication and toxic waste.

Angola's deputy ambassador Julio Lucas stressed the "crucial strategic role" the waterway plays in connecting Europe, Africa and the Western hemisphere, and the broadening list of illegal activities including environmental crimes.

The Security Council statement should send "a strong signal" of international resolve to address the security and economic threats to the region and the "potential links with terror groups in west Africa and the Sahel," he said.

Britain's deputy UN ambassador Peter Wilson said the two pirate attacks on April 11 struck the people, property and prosperity of seven countries — Malta and Liberia whose flags flew on the ships, Turkey, Greece and Nigeria where their cargo came from, and Egypt, the Philippines and Turkey which are home to the eight missing crewmen.

"It should concern us all that there were around a hundred similar incidents in the Gulf of Guinea last year," Wilson said.