I’d already stirred awake, from the persistent thudding of a 105 mm Howitzer blasting away on the dusty outskirts of Forward Operating Base Kalsu. It was already probably 35 degrees outside and the sun had only just come up, but we were staying in an air-conditioned cabin that was almost chilly. I rolled over and then the missile struck; a thunderous blast rattling the windows; a ballistic shudder vibrating for a nano-second through my body.

A young soldier, who the previous night had been reading from a huge Bible in the bed opposite, got up and was looking worried. “Was that outgoing or incoming” I mumbled. I haven’t been in Iraq long enough to distinguish between the two. He had. “Incoming” was the monosyllabic answer. He was already pulling his desert boots on and heading for the “duck and cover” shelter.

We followed him into the concrete tunnel, just outside the other side of the huge “T-bar” blast walls. We crowded in, sitting on the dirt floor with a dozen other young soldiers, many clutching their rifles. No one seemed to know what was going on.

One officer had a radio and listened intently for news, while spitting brown saliva from a wad of chewing tobacco lodged in his mouth. After a few minutes, word came through that the missile had slammed into one of the aluminium-clad buildings in the camp. Thirty-one soldiers had been hurt, two seriously. There was the annoying whine of a pilotless drone above us, probably controlled by a man, thousands of miles away. Then we heard F16 jets had been scrambled to investigate four more missiles that had been found nearby. They were pointing directly at the base.

After two sweltering hours, we were allowed to emerge from the bunker. I went to investigate the damage to the building. It was staggering: A huge gaping hole on one side and a charred air-conditioning unit lying on the floor, which thankfully had taken the brunt of the impact. It was while I was walking back to our accommodation that another massive explosion rocked the base. This time it was the F16s dropping a 500 lb bomb on a "suspicious" house near the launch site.

Kalsu, like many other bases across Iraq, regularly gets mortared and attacked by insurgent missiles. The army thinks this attack was the work of the Jaish Al Mehdi, a Shi’ite extremist group.

That night we piled into Chinook helicopters in utter darkness, for a short flight to a nearby farm. The troops ran across the ploughed field, as the whirring blades rained the fertile alluvial soil down from the inky sky. The only light up there was from other helicopters and the sprinkled broken glass effect of millions of stars. The soldiers met little resistance. All the men had fled, save for a man in his eighties.

Women and children were herded together in the farmyard, while troops with night vision goggles searched the outbuildings and houses in utter darkness. Half way through the search, there was a ripple of excitement. They’d caught some of the men trying to escape across the fields. They were interrogated by sweating, nervous officers. We could hear repeated shouts of “Shut up” from the house, but after a few minutes I was allowed to witness some of the questioning. The man was cuffed, kneeling on the floor of a room that had been turned upside down by the soldiers. Questions about his name, his age, and his military service were all barked at him. His eyes were wide and darted between the soldiers.

Few hearts and minds were being won on this farm tonight. Among those detained was a general in the Ministry of the Interior. The U.S. army thinks he is the leader of the rocket cell. I find it extraordinary that a senior member of the Iraqi government machine, which is armed and supported by the U.S., is directing attacks on American soldiers.

No one on the base seemed to think it was very unusual though, just as the missile attack was shrugged off. It’s all part of the daily grind of this conflict that is picking off American soldiers randomly and without warning, ensuring even within their bases they don’t feel safe and leaving many feeling they simply can’t trust anyone within the Iraqi government machine.

Watch my report

-- From Dan Rivers, CNN International Correspondent, in Iraq.