The UN secretary-general says an estimated $1.2 billion worth of cocaine transits through West Africa each year, and the Security Council is expressing "deep concern" about the drug trade's increasing links to terrorist groups.

The council issued a presidential statement Wednesday after Ban Ki-moon briefed it on the widespread risks to stability in a region where borders are porous, governments are poorly funded and extremists groups are active.

West Africa's recent rise as a route for cocaine and other drugs from Latin America to Europe has startled the international community.

Diplomats now point out that the region is producing its own drugs, including methamphetamine.

Ban says the region now has "more than a million users of illicit drugs," which hurts development in the vast region.

The region is seeing a "growing number of HIV infections due to drug injections," Yury Fedotov, executive director of the UN Office on Drugs and Crime, told the Security Council.

Fedotov also noted that the links between drug traffickers and extremist groups in the region are becoming "more obvious."

The presidential statement urges the countries in the region to work together to strengthen their borders and improve the fight against trafficking.

Ban contrasted the "weak intergovernmental co-ordination" in the region with the tight links among drug traffickers there.

The British ambassador to the UN, Mark Lyall Grant, said UNDOC has estimated that about 18 tons of cocaine transit through West Africa each year.

"While down from its peak of 47 tons in 2007, evidence shows that the trend is again upwards," he said.