Three of Africa's most notorious Islamic militant groups are joining forces, some American officials fear. According to General Carter Ham, head of the military's Africa Command, three insurgent groups -- Nigeria's Boko Haram, Somalia's Al Shabab and the Islamic Maghreb, which operates in North Africa -- are now sharing resources and could soon coordinate their attacks.

Each of those three organizations is by itself a dangerous and worrisome threat, Ham told an African Centre for Strategic Studies seminar in Washington on Monday. What really concerns me is the indications that the three organisations are seeking to co-ordinate and synchronise their efforts -- in other words, to establish a co-operative effort amongst the three most violent organisations … And I think that's a real problem for us and for African security in general.

All three groups have been connected to Al Qaeda in the past, and in December congressman Patrick Meehan (R-Pa.) said that Boko Haram is an emerging threat to the United States. On Monday, Ham noted that the Islamic Maghreb and Boko Haram, which both seem to be gaining force, pose more of a threat than Al Shabab, which was pushed out of another Somalian town by Somali and African Union forces on Tuesday.