US President George W Bush has said he understands how difficult the Iraq war is on the US, but that Congress must give his surge plan more time to work.
Mr Bush insists troops levels will only be decided by military leaders
Speaking in Ohio, Mr Bush urged politicians to not pursue a withdrawal now, urging patience until the head of US forces in Iraq reports in September.
Gen David Petraeus, who will make that report, has stressed that the extra troops have only just arrived.
Last week senators from Mr Bush's party joined opposition calls for a pull-out.
"I fully understand how tough the war is on the American psyche," Mr Bush said.
"And I know people are looking at their TVs and asking if it is worth it," he added.
"Yes it is," he insisted, saying that the conflict was vital to deny al-Qaeda a safe haven and ensure the safety of the American people's children and grandchildren.
Mr Bush asked the US to look beyond this week's upcoming status report on Iraq - an assessment of Iraqi progress toward meeting political and military objectives, which will be delivered to Congress on Thursday or Friday.
"I believe that it is in this nation's interests to give the commander a chance to fully implement his operations and I believe Congress ought to wait for General Petraeus to come back and give his assessment of the strategy that he is putting in place before they make any decisions," Mr Bush said.
"That's what the American people expect. They expect for military people to come back and tell us how the military operations are going."
'July is new September'
Calls for a withdrawal to begin immediately are growing in Washington, with four Republican senators last week adding their voice to those demanding a new plan.
And this week will see a contentious debate in the US Senate over a major defence spending bill.
In fact, such is the rise in pressure within Congress and among the US public that one official speaking to the Washington Post newspaper said that "July has become the new September".
Gen Petraeus has said it is too early to assess if the surge is working
The BBC's James Coomarasamy in Washington says that the president's call for a ceasefire in the political battle cannot mask the growing sense of urgency in the White House about the need to stem the flow of Republican defections on Iraq.
Vice-President Dick Cheney and other senior administration officials have been in Congress during the day urging senators to remain loyal.
And even before Mr Bush's speech White House aides were playing down the July report, calling it a "snapshot" and emphasising that since the surge, under which an additional 30,000 US troops have been deployed in Iraq, has only just begun, not too much should be expected just yet.
"You are not going to expect all the benchmarks to be met at the beginning of something. I'm not sure everyone's going to get an 'A' on the first report," White House spokesman Tony Snow said.
Long term battle
Mr Snow went so far as to say that even the fuller report - in which Gen Petraeus, head of US forces in Iraq, and Ryan C Crocker, US ambassador to Iraq, will testify before Congress on 15 September - is also not "the drop dead date" by which everything should be finished.
On Monday, speaking to the BBC, Gen Petraeus also called for patience, warning that fighting the insurgency is a "long term endeavour" which could take decades.
He said there was evidence that the recent troops surge was producing gains on the ground.
But he also insisted it was not yet possible to see the full effect it was having as it took until mid-June to get all of the additional troops and equipment on the ground.
"I think again we need to see where we are in September when we'll have had a couple of months of all of our forces," he said.