Wanted: a good copy editor

Here's a great example why copy editors are important and why a single, imprecise word can change the whole meaning of a sentence.

Take this BBC News story;

The article began about how Chad's leader Idriss Déby called for next month's African Union summit to be moved from Sudan (against whom Chad recently declared war) to Nigeria. Déby accused Khartoum of backing a Chadian rebel group.

But, the BBC wrote, Sudan's foreign minister told the BBC that Sudan's army had fought with Chadian rebels when they refused to either disarm or leave Sudan.

Does the phrase "Sudan's army had fought with Chadian rebels" mean they fought alongside the rebels or against the rebels?

Only from other parts of the article can you presume that they meant 'against.'