The army general nominated by President George Bush to be the new US commander in Iraq has warned of tough days ahead but said the situation is not hopeless.
Lt Gen Petraeus said any progress in Iraq would take time
Lt Gen David Petraeus was giving evidence at his confirmation hearing before the Senate Armed Services Committee in Washington.
If approved by Congress, he will be in charge of carrying out President Bush's new strategy in Iraq.
Some 20,000 US troops are to be sent to Iraq to try to secure Baghdad.
The general, who is set to take over from Gen George Casey, reiterated his backing for the deployment of more US troops in Iraq.
"None of this will be rapid. The way ahead will be neither quick nor easy. There undoubtedly will be tough days," he told senators.
"The situation in Iraq is dire. The stakes are high. There are no easy choices. The way ahead will be very hard," Gen Petraeus said.
"But hard is not hopeless."
On the question of what would happen if the strategy failed, Gen Petraeus made it clear that he would consult with the defence secretary on how to respond.
However, he said there were signs that the Iraqis were already stepping up to the challenge.
Morale among the US military was good, Gen Petraeus said, adding he believed they could achieve their mission.
The general, who has already served in Iraq, is widely respected by both Republicans and Democrats and his nomination is expected to be approved by Congress, says the BBC's Jonathan Beale in Washington.