The last US combat brigade in Iraq crossed the border into Kuwait on Thursday, fulfilling President Obama's pledge to end combat operations by the end of this month.
The troops' departure has left many Iraqis apprehensive, with some predicting a rapid regression towards sectarian fighting.
Iyad Othman, a Fallujah policeman, said: "Now that they are gone for good, the situation will not continue to improve. They are surrendering the country to the Iranians."
In Baghdad the mood remains fearful. "It scares me to think that the Americans are leaving," said Umm Ali, 33, in the streets of Arasat, a well-to-do suburb. "If 144,000 soldiers could not control the situation here, how will things improve when there are only 50,000 here and they all stay in their camps?
"Obama did not think about Iraq's interests when he pressed ahead with this withdrawal," she said. "It is a very bad decision, and so is the timing. He should wait for a new government to be formed, one that is strong and can establish – then respect – the rule of law."
Ali Fidel, 40, a public servant in the agriculture ministry, was dismissive of US claims that Iraqi forces had been readied to fill the void left by departing US troops. He said: "If we take a look at the last two months in Iraq, security has now deteriorated to what it was in 2008. I think it will collapse after 31 August, and the country will then be in chaos.
"The Iraqi forces are not ready to work. They don't have the equipment to protect themselves, so how will they protect the civilians?"
Muner Salam, 50, a doctor from Mansour in west Baghdad, said: "Since 2003, Iraq has been destroyed day by day. Political parties and officials are too busy feuding over how to improve their own positions. The Americans cannot control it and now they decide to leave it to ruin.
"There is no government, no infrastructure, and daily explosions targeting doctors and judges. I am pessimistic. I think the country will face enormous challenges, and will not gain victories quickly. It will take a long time to control security."