The US wants Iraqi security forces to take charge of security duties. Top members of the US government have offered their backing to President George W Bush's policy in Iraq, weeks before his party faces mid-term polls. This violence is going to go on for a long time
Defence Secretary Donald Rumsfeld was among several officials defending the government's Iraq policy as adaptable.
The US envoy to Iraq earlier said Iraq could be stabilised, despite setbacks.
A top Republican has meanwhile joined Democrats in criticising Mr Bush in a month when 90 US troops died in Iraq - the highest toll since November 2004.
US National Security Adviser
Three hundred Iraqi troops have also died in October, and some estimates say sectarian attacks now claim an average of 40 Iraqi lives every day.
According to the BBC's Justin Webb in Washington, the Bush administration is trying its best to suggest it has a plan to end the violence.
'Violence to continue'
Several top administration officials discussed Iraq with a gathering of conservative talk radio hosts at the White House on Tuesday.
Defence Secretary Donald Rumsfeld was asked why President Bush appeared to have abandoned the Republicans' recent slogan that the party was planning to 'stay the course' in Iraq.
'I suppose the concern was that it gave the opponents a chance to say, 'well, he's not willing to make adjustments' - and of course just the opposite is true,' Mr Rumsfeld said.
Baghdad diary: What options?
President Bush echoed this view in an interview with CNBC TV, saying he had been 'talking about a change in tactics... ever since we went in'.
National Security Adviser Stephen Hadley meanwhile said the violence in Iraq is unlikely to end during Mr Bush's presidency.
'Is there going to be peace? Is there going to [be] the end of any violence? Of course not. This violence is going to go on for a long time,' Mr Hadley said.
But, he added, the US hoped Iraqi institutions would eventually be able to contain the threats to the country's security.
'Verge of chaos'
A top Republican Senator has meanwhile argued that the White House has lost its direction in Iraq.
HAVE YOUR SAY
Having invaded the country I feel we are under some kind of obligation not just to abandon it
Jo Wiltshire, London
'We're on the verge of chaos and the current plan is not working,' Senator Lindsey Graham said.
He said Mr Rumsfeld and the US military commanders in Iraq must 'come up with a game plan' to end the fighting.
Our correspondent says Senator Graham's eye-catching intervention appears to have been timed to coincide with a TV appearance by US officials defending Washington's policy in Iraq.
Gen George Casey told a press conference in Baghdad that Iraqi forces should be able to assume responsibility for security in the next 12 to 18 months, with minimal aid from the US.
Appearing alongside him, US envoy to Iraq Zalmay Khalilzad said stability in Iraq remained a realistic goal.
He said there would be setbacks, but the aim of creating a multi-ethnic and multi-faith Iraq remained unchanged.
Our correspondent says the Republican party is hoping that Tuesday's efforts to defend policy in Iraq will convince the party's supporters that all is not lost there, before mid-term polls in two weeks' time.
An opinion poll conducted during the last few days for CNN suggests that only 20% of Americans think the war is being won. The figure was 40% a year ago.