Since the curfew in Baghdad was extended indefinitely, the city has been dotted with military checkpoints.
By Adam Brookes
BBC News, Baghdad
Police have been stopping the few vehicles on the streets
The curfew means no vehicles at all can move - except for those of the police and military.
That, of course, makes it much harder for militiamen to move around.
They cannot transport supplies or ammunition. They cannot carry the 107mm rockets that are plaguing this city to launching sites.
If they try, they risk being spotted by American overhead surveillance - perhaps by unmanned drones or helicopters.
The American military released graphic footage on Saturday, filmed from the gun camera of an Apache attack helicopter, which showed militiamen on the move. And the missile which killed them.
Fresh food fading
For Baghdad's civilians, life grows more miserable by the hour.
The authorities appear to be allowing a little foot traffic but for the most part Baghdad's streets are empty. Most of its businesses are closed, as are schools.
Some neighbourhood markets are open, and in calmer parts of the city people are leaving their houses to shop.
But the curfew means no fresh food is coming into the city.
The vegetables on the stalls are now several days old, prompting expression of disgust from shoppers.
Nonetheless, they are selling out fast as people stock up for the coming days.
"Just onions and garlic left," said one after visiting a market in east Baghdad.
And prices are starting to rise. A kilo of tomatoes usually costs 1,250 Iraqi dinars (about $1). This morning, at the east Baghdad market, they were selling for 3,000 dinars.
A man out shopping said he had fought his way through a crush of people surrounding a stall that still displayed a pile of ageing tomatoes.
The boy working the stall refused to serve him, saying he needed to sell to local women who were trying to feed their families.
The man found his frustration tempered by the boy's insistence on serving those who needed the food most.
Chicken and petrol
Bakers in the same district say that in another two days they will no longer be able to bake bread.
Baghdad roads were empty of vehicle traffic on Sunday
Their flour will run out, and so will their kerosene. The baking and buying of bread is a neighbourhood ritual. It stops, Baghdadis say, only in abnormal, frightening times.
Each Iraqi family is guaranteed a supply of staples through a government distribution system - a holdover from the regime of Saddam Hussein.
Some families keep in their homes large stocks of flour, rice and lentils, obtained through their government ration cards.
Other families do not, preferring to sell those stocks for cash. The latter will find it harder to manage if the curfew lasts.
And that staple of Iraqi cooking, chicken, is getting harder to come by.
In supermarkets closed by the curfew many frozen chickens have spoiled. The freezers have not been running because nobody was there to turn on the generators when the power supply cut out - as it does several times a day.
Electricity shortages plague Baghdad at the best of times. Now people are unable to drive to petrol stations to fill jerry cans for generators. Even if they made it to the petrol station they would find that petrol supplies are running low.
Feeling the heat
Those who would normally work complain they are stuck at home, listening to long discussions between neighbours of the rights and wrongs of Prime Minister Nouri Maliki's confrontation with the militias.
They are following events on television, when the electricity supply allows.
Baghdad is getting hotter. The spring temperatures are already into the nineties. The city's paralysed.
Despite the curfew, another rocket has just crashed into the Green Zone. The American alarms are echoing across the Tigris river. And the power has cut out again.
Just a week ago, in odd moments, Baghdad felt like something resembling a normal city. Those moments now feel very far away indeed.