In pictures: Operation Ivy Serpent

1 of 8 Operation Ivy Serpent aims to sweep central Iraq for insurgents who have been targeting US troops

2 of 8 More than 50 people were arrested and four killed in the operation which began on Saturday night

3 of 8 The US believes opponents of the coalition are planning attacks to coincide with important public holidays from the Saddam era

4 of 8 It is the fourth major operation to try to stem the attacks which have killed dozens of coalition soldiers

5 of 8 As well as the arrests, US soldiers are scouring the countryside for weapons caches

6 of 8 Among those arrested were two former generals and a senior Baath party official

7 of 8 During the operation, troops came under fire from rocket propelled grenade and automatic rifles

8 of 8 The operation came as Iraq took its first steps to self-rule with a meeting of the Iraqi Governing Council