Islamist militants are increasingly funding themselves through kidnapping, with al Qaeda's north African wing likely to have brought in tens of millions of dollars in ransoms in the past few years, a senior U.S. Treasury official said.
The United States estimates militant organisations received $120 million in ransoms over the past decade, including to al Qaeda in the Islamic Maghreb (AQIM) in recent years, said David Cohen, undersecretary for terrorism and financial intelligence.
Kidnapping for ransom was an "urgent threat", particularly in the Sahel, a belt of land spanning nearly a dozen of the world's poorest nations on the Sahara's southern rim, Cohen told reporters in Berlin on Tuesday.
"It is what has become perhaps the most challenging and fastest growing technique that terrorist organisations, in particular the affiliates of al Qaeda in North Africa and in Yemen, have been using to fund themselves over the last couple of years."
Cohen said the average ransom had gone up consistently over the years and was in the range of $5 million per payment.
"So, it is a growing and really quite urgent threat, particularly in North Africa, in the Sahel and in Mali in particular, where AQIM has now managed to claim dominion over a large territory."
AQIM emerged out of Algeria's civil conflict and has expanded south into the Sahara, raising its profile in recent years with hit-and-run attacks and kidnappings of westerners.
Militant groups have benefited from lapses in security across the region as countries transition from years of dictatorship to more democratic government.
Cohen, on a week-long trip that includes stops in Britain, France, Germany and Italy, said he was talking with other governments in the hope of developing a unified approach to the kidnapping problem.
While the U.S. government has a policy of not paying ransoms, some European governments do so.
Talks were centred around steps to prevent kidnappings happening in the first place, the handling of hostage situations when they occur, and the tracing of financial flows when ransoms are paid, Cohen said.
Iran and Syria were the other main topics of discussion with his European counterparts, he said
Sanctions against Syria over the past 18 months had taken a "significant bite" out of the government's finances, he said, declining to give figures. "You have a situation where the Syrian government is spending at a greater rate.
"They are spending on security needs, on providing subsidies to their citizens, at the same time that the revenue side of the ledger is being significantly restrained. The natural impact of that is that their reserves are depleting."