Thousands of Iraqi security forces have been deployed nationwide a day after the US military formally ended its combat operations. Iraqi officials are confident the country's own soldiers and police are ready to uphold national security.
Tuesday's deadline was to some extent a symbolic one.
Iraqi authorities intensified and increased military checkpoints on Wednesday.
The 50,000 US soldiers staying on in Iraq for another 16 months remain heavily-armed, but will only serve as advisors to their Iraqi counterparts.
A spokesman for Baghdad's security plan said that Iraqi security forces will assume additional responsibilities now that many US forces have withdrawn.
General Qassim Atta, Spokesman Baghdad Security Plan, said, "Today US combat forces were completely withdrawn from Iraq. Iraqi security forces will adopt additional security responsibilities that were previously provided by US troops."
Iraqi security forces have already taken the lead since a bilateral security pact came into force last year. US soldiers began withdrawing from many Iraqi towns in June last year.
Iraqi military officials are confident the transition will be smooth.
LT. Gen. Nasir Al-Ibadi, Iraqi Deputy Chief of Security, said, "I don't think US withdrawal has come too fast. We have been training and actually combat for counter insurgency and counter terrorism since 2005 and we have been prepared for this by the coalition, by the Americans."
Iraq's Foreign Minister is also confident his country's troops can maintain security in Iraq.
Hoshiyar Zebari, Iraqi Foreign Minister, said, "I believe Iraqi security forces are capable of relying on themselves, taking care of their own affairs, and maintaining internal security in Iraq. They did an excellent job for securing the March general election. The bulk of the work in fact was carried out by Iraqi security forces with minimal support from US forces."
US officials say Washington has a long-term commitment to Iraq, and the military drawdown will allow diplomats to take the lead in building economic, cultural and educational ties. But before that can happen, a new Iraqi government must be formed.