From the Guardian:
From west African coastal states such as Guinea-Bissau the drugs pass through Mauritania, Mali and Niger before ending up in Libya or Egypt. From there, law enforcement officials suspect the drugs are hidden in containers on board cargo ships, which are less likely to be searched than those from Latin America.
Intelligence agencies are studying claims that the airstrip in Mali is under the control of one of al-Qaida’s most powerful franchises, raising concerns that Africa’s burgeoning role in the cocaine trade is now funding terrorism.
It is not only al-Qaida that may be involved. A briefing prepared for the US Congress speculated that west Africa’s substantial Lebanese trading community – strong supporters of Hezbollah – have been buying the drug from the paramilitary group Farc, the Revolutionary Armed Forces of Colombia.