Shi'te militias bite back

[Watser?]

Saturday was one of the worst days for US troops in Iraq in terms of numbers of soldiers killed:

At least 20 American service members were killed in military operations Saturday in the deadliest day for U.S. forces in two years, including 13 who died in a helicopter crash and five slain in an attack by militia fighters in the holy city of Karbala, military officials said.

Now the helicopter going down is probably just an accident, it is not the first thing this happened. But FIVE soldiers killed by militiamen in Karbala? Karbala is very definitely Shi'ite territory. This might be only the start of a new Shi'ite insurgency, which was only to be expected really. Declare the militias to be your enemy and they start behaving like one.
It might just have been a fluke though, the Mahdi militia seems to be lying low:

The decision by al-Sadr to lower his force's profile in Baghdad will likely cut violence in the city and allow American forces to show quick results from their beefed up presence. But it is also unlikely in the long term to change the balance of power here. Mahdi Army militiamen say that while they remain undercover now, they are simply waiting for the security plan to end.
"If the Mahdi Army is attacked, they will defend themselves," said Sheikh Abdul Razzaq al-Nidawi, a senior al-Sadr official in Najaf. "American troops are the enemy troops . . . if the Americans want armed resistance, we are ready, but we will work hard not to get involved in an armed opposition and we will work hard to endure the pressure even if we make sacrifices to keep our people and country safe."

Oh and a British soldier was killed in Basra Saturday. Unfortunately this is not a new phenomenon though, Shi'ite militias in Basra have started attacking the British a long time ago.