The prime minister has visited a hospital where some survivors of the Cumbria shootings are being treated.
Derrick Bird, 52, killed 12 people and wounded 11 others on Wednesday before shooting himself.
David Cameron and Home Secretary Theresa May met some of the police officers who responded to the killings.
The PM said he was visiting to show the government cared, adding that the community would need help through what would be "a very, very difficult time".
The atrocity, Britain's worst mass shooting since the one in Dunblane in 1996, has shocked the county and the nation.
Mr Cameron visited Whitehaven's West Cumberland Hospital, where he spoke to one of Bird's victims - a woman called Christine who is being treated for gunshot wounds and who also lost neighbours in the shootings.
"She wants to go home and start to rebuild her life," he said.
"There are incredible stories of bravery here and an amazing community that has been torn by this but will eventually come through this like other communities have."
He then travelled to Workington police station, where he was met by Cumbria Chief Constable Craig Mackey and received a briefing on the investigation.
Mr Cameron paid tribute to all of the emergency services involved and spoke to two of the armed officers who had tried to follow Bird as he sped around the Cumbria countryside.
One of the officers said: "It was so fast. It was unbelievable. We were no more than 36 minutes behind him.
"We kept coming across where he had been. There were just too many roads and too many options to go down."
Mr Cameron said the communities in west Cumbria had suffered the "most appalling tragedy".
"It will have a huge impact on the community, and I wanted to come here to show that the government wants to listen and wants to show how much it cares about what has happened here," he said.
When asked about gun ownership laws, Mr Cameron said the government would look at "all of the issues", adding that the UK already had very tough controls.
Bird, from Rowrah in Cumbria, was the legal owner of the shotgun and rifle he used in the killings.
He left his job at Sellafield after being convicted of stealing from the nuclear plant for which he was given a suspended sentence.
The Home Office says people sentenced to three months or more in prison are automatically banned from possessing a firearm for at least five years, although Bird's conviction was spent.
"Mr Bird was given a suspended sentence for theft in the 1990s so did not serve time in prison, nor did he have any apparent history of violence, meaning he was entitled to hold a firearms licence," a spokesman added.
Police are continuing to investigate what led the taxi driver to shoot his victims, who were all killed on Wednesday morning.
The death of one of the victims - cyclist Michael Pike - was witnessed by children, including a nine-year-old boy, who said Bird had stared at him "like a hawk" as he drove through Seascale.
Jordan Williams told BBC Radio 4's Today programme: "I just saw a man just coming up the hill on his bike and then a crazy, like, taxi just came up and [Bird] shot his back wheel and then shot him in the cheek and then he just drove off.
"He stared me in the eyes, and my mum, and he just kept on driving and he just zoomed off."
After the killings, Bird's body was found in a wooded area in the village of Boot.
Detectives said on Thursday that his motive appeared to be a mixture of "grudge and random".
Fellow taxi driver Mark Cooper, a friend of the gunman, said Bird had told him he feared he would be jailed over an undeclared sum of £60,000 in his bank account.
"He said: 'They have caught me with £60,000 in the bank, the tax people'. He just said: 'I'll go to jail'.
"He just asked me if he could handle jail. He didn't want to go."
A Cumbria Police spokesman confirmed that detectives were looking at the killer's finances and involvement with HM Revenue & Customs.
At least three of the people Bird shot dead - his twin brother David, the family's solicitor Kevin Commons and fellow taxi driver Darren Rewcastle - were known to him.
He is thought to have first killed his brother in Lamplugh before returning to Frizington, where he opened fire on Mr Commons.
He then drove to Whitehaven where he shot Mr Rewcastle, before shooting the rest of his victims in seemingly indiscriminate attacks.
The family of James and Jennifer Jackson - a retired couple whom Bird killed in Wilton Village - have released a tribute to them.
It said: "They were wonderful, quiet, loving people right at the heart of the communities of Haile and Wilton.
"Everyone here is in shock at this tragedy, trying to make sense of all that has happened."
The family of 66-year-old Jane Robinson, who was shot in Seascale, have also paid their tributes.
Barrie Robinson, her twin sister, said: "Jane was such a caring, considerate and generous person in the local community and always had time to help people.
"She was the best sister I could ever have and as twins we were especially close."
Seven people who were shot but survived remain in hospital.
Doctors have said five of those are in a comfortable condition at either Whitehaven's West Cumberland Hospital or the Cumberland Infirmary in Carlisle.
Two people are being treated at a hospital in Newcastle. One of the patients is said to be comfortable, while the condition of the other is unknown.
Some reports have suggested that Bird might have been involved in a dispute with a family member over a will, which could have sparked the shootings.
But speaking to BBC Radio 5 live, Joy Ryan, a relative of Bird, dismissed suggestions of a family feud, saying: "Maybe a row that went on the night before, not a feud."
In a statement issued by police, David Bird's daughters have also insisted there was no family feud.
Speaking on Thursday, Det Ch Supt Iain Goulding said investigators might never discover the full reasons for his actions.