"And to the extent that the federal government can help you, we want to do so."
The blazes in Southern California have killed at least five people and caused more than $1bn in property damage, scorching 172,000 hectares of countryside and causing an estimated 500,000 people to leave their homes.
More than 500,000 people evacuated
More than 172,000 hectares of state's countryside scorched
More than 1,700 buildings destroyed and emergency declared in most of California
Three dead and another 40 injured, including firefighters
Al Jazeera's Kelly Rockwell, reporting from southern California, said the disaster had been declared a federal emergency, meaning that local residents will receive federal assistance along with help from the state government.
In San Diego's hard-hit community of Rancho Bernardo, Bush stood with Jay and Kendra Jeffcoat near the rubble of what used to be their home.
"Those of us who are here in government, our hearts are right here with the Jeffcoats," he said, his arm draped around Mrs Jeffcoat. He then kissed her on the head.
Later, Bush shook hands at a makeshift disaster assistance centre where government agencies and private companies are providing help to residents.
From there, the president's motorcade passed charred hillsides on the way north to Escondido, where he assessed that area's damage and addressed the public and about 200 firefighters.
"We can't thank people enough for putting their lives at risk to help a neighbour," Bush said.
The Federal Emergency Management Agency (Fema) had 1,000 people on the ground in San Diego.
Both Fema and Bush were criticised for being slow to respond when Hurricane Katrina struck New Orleans and the Gulf Coast region in 2005 and their response to the California fires is likely to be assessed in this light.
|Round-the-clock crews have been brought in|
to fight some of the fires [EPA]
"There's all kinds of time for historians to compare this response to that response," Bush said.
Arnold Schwarzenegger, the California governor, standing next to Bush, said the president had reached out before Schwarzenegger had even called on him.
"I call this quick action - quicker than I expected, I can tell you that," Schwarzenegger said.
Bush responded: "It makes a significant difference when you have somebody in the statehouse willing to take the lead."
It was not clear whether this was a swipe at Kathleen Blanco, the Democratic governor of Louisiana, who the White House blames for many of the problems after Katrina.
Blanco, when she learned of Bush's remark, said: "I was the only game in town, leading for nearly a week without the president's help.
"Of all the lessons learned from Katrina now being put into place in California, I would hope the one he would remember is that politics has no place in any disaster."
While the California fires have been the first natural disaster in the US to approach the seriousness of Hurricane Katrina, the storm affected a far larger geographic area and knocked out all communications and most of the infrastructure.
It impacted a relatively poor population and states that were much less-prepared for a natural disaster.
In California, some of the fires remain at very low containment and round-the-clock crews have been brought in to fight them.
But a shift in the wind, from hot, dry Santa Ana gusts blowing in from the deserts to an onshore flow of cooler, more moist air coming from the Pacific, has helped firefighters hold the line of the flames.
Los Angeles county reported progress, cancelling wind warnings for the first time since the weekend.
Top wind speeds fell to below 80kph after gale force gusts hit 130kph.
San Diego county officials said that even when the fires were extinguished they would face a major clean-up and huge costs.
|A blazing hillside is seen from the entrance of Camp Pendleton on Wednesday [AFP]|