US Defence Secretary Donald Rumsfeld told Iraqis in an interview today attacks on coalition forces would not drive them out and that Saddam Hussein would never return to power.
At the same time, Russia added weight to opposition to a US proposal seeking more peacekeeping troops for Iraq from other countries.
"The coalition will not be dissuaded from its mission in Iraq, not by sabotage, not by snipers, and not by terrorists with car bombs," Mr Rumsfeld said in the interview videotaped for broadcast by Iraqi Media Network.
"The Hussein regime is finished. They will not be returning," he said, adding that "remarkable progress" had been made in Iraq since his last visit four months ago.
While saying he saw no need to commit more US troops to Iraq, he has urged allies to send an extra 15,000 troops. But opposition to Washington's draft UN resolution calling for troops and cash has been led by the most powerful opponents of the war which toppled Saddam in April.
Russian Foreign Minister Igor Ivanov joined the leaders of France and Germany in rejecting the draft, saying it "still needs further, very serious work".
French President Jacques Chirac and German Chancellor Gerhard Schroeder said yesterday Washington's draft resolution did not cede power quickly enough to Iraqis or to the United Nations.
British Foreign Secretary Jack Straw said today he was optimistic agreement could still be reached on the draft proposal, which would authorise a multinational force to contribute to "the maintenance of security and stability in Iraq". The United States would retain overall military command.
Britain also said it would send 120 extra soldiers to Iraq to join its 11,000-strong force already there.
Mr Rumsfeld also visited US troops at Tikrit, Saddam's hometown and former powerbase, and the northern city of Mosul, where Saddam's sons Uday and Qusay died in a shootout with US soldiers from the 101st Airborne Division in July.