The Met Police's deputy assistant commissioner Brian Paddick has held a "measured and positive" meeting with community representatives in Stockwell.
Mr Paddick said people understood the officers' situation
He held talks after Brazilian Jean Charles de Menezes, 27, was shot dead at Stockwell Tube station by police who mistook him for a terror suspect.
Mr Paddick warned that while it was "unlikely", he could not guarantee a similar tragedy would not happen again.
Council officials, Muslim and Latin American leaders were at the meeting.
Members of the local police consultative group were also present.
Mr Paddick said: "It was a very calm meeting. People were very understanding of the circumstances that these officers found themselves in.
"We expressed our sympathy to the family of the person who was tragically killed. It was a very measured meeting, but a very positive meeting."
Mr Menezes, an electrician who was not involved in terrorism, was killed after running into the underground station on Friday.
He had been followed by police who had placed his flat under surveillance, believing it was connected to Thursday's failed attacks.
Met Police Commissioner Sir Ian Blair has apologised to Mr Menezes's family, describing his death as a "tragedy".
But Mr Paddick said the police "would seek to avoid this ever happening again but we can't guarantee it won't", however he said a repeat was "unlikely".
He said: "There were very particular circumstances surrounding this shooting. This person was seen leaving premises we had under observation - it wasn't a random matter."
Of the officers involved in the shooting, Mr Paddick said: "Clearly those police officers are being cared for. They've been visited by senior officers which they were very grateful for.
"We will give them all the support we can."
The meeting took place after Stockwell MP Kate Hoey had asked police to reassure members of the local community that a similar incident would not happen again.
The former sports minister said it was important Metropolitan Police Commissioner Sir Ian Blair now addressed local people.
Ms Hoey, MP for Vauxhall, is worried the Scotland Yard action could jeopardise attempts by the local police force to build links with the Stockwell community.
"All the very good work that has been going on over the past few days in the community with representatives of mosques and other faith groups - it is important that does not end.
"That is why it is very important that we almost differentiate between Scotland Yard, and what they do, and our local police, who have been superb."
She said local commanders had established very good links with the community, which had continued over the past few days, and which she did not want to see end.