What is the enemy strength in Mali that has the French on their heels?

A meeting engagement, a term used in warfare, is a combat action that occurs when a moving force, incompletely deployed for battle, engages an enemy at an unexpected time and place.

Wow.  

The French are fully engaged in Mali now.  From almost a brigade of troops on the ground to at least a few dozen airplanes providing air support with helos and an unknown number of ground vehicles involved this is turning into something fierce.

The way that this developed seems to caught many off guard.  Myself included.  As a matter of fact this has all the hallmark of a meeting engagement that turns into a savage furball.

The UK is rushing to assist as is the US and reportedly Canada.  What other members of the EU are doing is beyond me but I would be surprised if they didn't become involved soon.

One thing is certain though.  It puts this story in a whole new light.

On July 8 the Washington Post reported the story of the April 20 death of three U.S. Special Operations Forces service members in Mali, a North African country known for a growing Islamic insurgency, and more recently the scene of a coup in March. The soldiers’ deaths are believed to be the result of vehicle accident, as their rented Toyota Land Cruiser went off a bridge in the pre-dawn hours, and plunged into the Niger River.While tragic, what is curious is that this accident and these deaths came a full month after the Obama administration officially suspended military relations and humanitarian assistance with Mali’s unstable government. Even more curious, along with the bodies of our soldiers found in their vehicle were the bodies of three dead women, all of whom have been reported to be Moroccan prostitutes.

I don't know what really happened and we probably never will.  I'll bet there was alot more to this story than meets the eye though.

But the subject of this post is what's really causing me the most heartburn.  What is the enemy strength?  How were they able to gain enough strength to scatter government forces?  And how were they able to mount this offensive without us detecting them?