London mayor Boris Johnson described the actions of rioters who prevented firefighters from reaching burning buildings earlier this week as "demented" today.
Speaking as he visited Stoke Newington fire station in north-east London, he praised the "heroism" of crews who battled to extinguish blazes started by mobs across the capital.
London Fire Brigade received 2,220 calls - about 15 times the usual amount - on Monday night, and attended 1,500 incidents.
Mr Johnson said the challenge to firefighters during the riots had been "unprecedented".
He added: "London Fire Brigade was able to cope comfortably within its strength with the biggest fire challenge this city has faced for many, many, many years.
"I congratulate them on their management, on their organisation, on the dynamism of the men and women who serve, the firefighters.
"I think the firefighters have done the most incredible job and there are many heroes in the story of what has happened in the last few days, but London Fire Brigade is out here, at or near the top."
Some of the 49 staff at the station, who were among the first at the scene of the fires in Tottenham where the riots started on Saturday night, told the mayor how they came under attack themselves.
Mr Johnson said: "What strikes me as so barmy is just the idea that you could actually be at physical risk from people who are there on the scene.
"It's crazy, I mean what kind of mentality is that in people who attack firefighters. They are literally out of their skulls.
"They deserve very serious penalties in my view."
He was told that luckily only a few minor injuries were sustained by firefighters.
But he exclaimed "you are joking" in disbelief when he was told that a firefighter on her way to work at Clapham fire station was attacked and threatened with a gun.
As he chatted to firefighters, Mr Johnson was invited to sit in one of the station's fire engines but said he "had better not". However it appeared the temptation was too great for him as he then quickly clambered up on to one of the front seats.
He was told London Fire Brigade had used 120 appliances to attend all the riot-related call-outs, with the more serious fires using 10 or 11 at a time. Between 8pm on Monday and 1am on Tuesday they attended 10 large fires simultaneously.
Forty-nine fire appliances were also kept in reserve in case of other incidents and no other fire services had to be drafted in.
Mr Johnson said they were running a "tight ship".
"That is amazingly efficient. It's very impressive," he added.
Speaking more generally about the disorder, the mayor said: "We've got to make sure that we support our firefighters, we support our police, and that we use this whole business to look at the real issues that lay behind it.
"There are people on the left, people on the right, who will both find causes of the riots that will satisfy them ideologically. There's a rich banquet of causation here.
"Let's get it all out there. Let's look at what went wrong. Let's use this experience to make London an even better place."
London Fire Commissioner Ron Dobson, who was also present at the station, said: "London Fire Brigade is here to protect Londoners. "London Fire Brigade will always do the best it possibly can."