National police firearms experts are to investigate Cumbria Police's response to Derrick Bird's fatal shooting spree, the prime minister has revealed.
The chief constable of Cumbria, Craig Mackey, has asked the Association of Chief Police Officers (Acpo) to co-ordinate an external review.
David Cameron also confirmed that the government is already reviewing the UK's gun laws but warned against a "knee-jerk reaction".
The reviews would be made public.
He said Mr Mackey had written to Acpo president Sir Hugh Orde seeking a review that would examine the "police firearms response and firearms tactics".
His comments came at prime minister's questions and after MPs took part in a minute's silence for the 12 victims of taxi driver Bird.
Mr Cameron had been asked by Labour's Acting Leader, Harriet Harman, if the government had plans to review the gun laws following the tragedy.
He said: "We need to be clear first about the full facts of the case. We also need, I think, to determine the type and the scope of reviews that will take place after this tragedy.
"Of course the Home Office will look again at the gun laws in the light of that."
He said people needed to steer away from "leaping to conclusions" but appropriate action was needed.
He said: "We do have some of the tightest gun laws in this country, but of course we should look again.
"In the end what we must do is make sure we do the right thing by the people of west Cumbria and make sure that they are properly served in the things that we decide as a government."
He said the current rules were already very strict and there were some factors which could not be covered by legislation.
"If we're looking for what the problem is, the problem is clearly we have a huge number of guns in our society we need to get rid of, and clearly there was an appalling problem in this case, whereas I've said a switch flicked in someone's head.
"You cannot legislate against that, but yes, let's look at every aspect and make sure we have the robust laws that we need," he said.
Jamie Reed, the Labour MP for Copeland, told BBC Radio 4's The World at One that the local community needed to play a part in shaping any inquiry into the killings.
He said he had met Mr Cameron following his announcement in the Commons and they had discussed ways of ensuring the community had the chance to "say what it needs to say".
He said the community was "grief-stricken" but determined, adding: "I don't think it's for any politician to say what shape this inquiry should be. It's up to my constituents."
Questions had been asked about whether police did enough to stop Bird, who had licences for the two weapons he used during the rampage - a shotgun and a .22 rifle.
Cumbria's deputy chief constable, Stuart Hyde, has said that officers did all they could and they were powerless to stop the killer as he moved throughout Cumbria.