Tunisia started deploying armed police around tourist sites on Wednesday after last week's massacre at a beach resort, as authorities finished identifying all 38 people killed in the jihadist attack.
A British military plane carried home eight bodies of its nationals killed in the assault, with Tunisia's health ministry confirming that 30 Britons were among the dead.
vOn Friday, 23-year-old Seifeddine Rezgui went on a bloody rampage in the popular Port El Kantaoui resort, shooting dead 38 foreign tourists with a Kalashnikov assault rifle at the five-star Riu Imperial Marhaba hotel.
It was the second attack on tourists in Tunisia claimed by the Islamic State group in just three months, after IS claimed a March attack on the National Bardo Museum that killed 22 people.
In its wake, Tunisian authorities vowed new heightened security measures, including 1,000 armed officers to reinforce tourism police -- who will be armed for the first time -- at hotels, beaches and other attractions.
"This morning, we started to deploy and armed police will be in hotels within the hour," interior ministry spokesman Mohamed Ali Aroui told AFP.
Wearing T-shirts with the words "Tourism police", armed officers on quadbikes patrolled the beach of the Imperial hotel, as well as other sites nearby, AFP journalists said.
But at the site of the ancient city of Carthage, the beaches at Gammarth and the stunning Sidi Bou Said neighbourhood outside Tunis, no new deployment could be seen by mid-morning, the journalists said.
Security officials "are busy deploying at Hammamet," a seaside resort in the south of Tunis, Aroui said.
President Beji Caid Essebsi said Tuesday that security had been boosted in other areas for the Muslim holy month of Ramadan.
But authorities had not expected beaches to be targeted, he told French radio.
Several witnesses said the beach attack lasted more than 30 minutes before the gunman was shot dead, but officials say police were on the scene within minutes.
- 30 Britons among dead -
Signup to our newsletter and follow us on Facebook and Twitter!
The health ministry said Wednesday it had identified all 38 victims, with British tourists accounting for the lion's share of the dead.
"All the bodies have been identified. Among them are 30 Britons," said the ministry's director of emergency services, Naoufal Somrani.
"All the victims were staying at the hotel. They... had travelled here with tour operators," Imperial hotel owner Zohra Driss said.
The bodies of eight Britons were flown Wednesday to a Royal Air Force station north of London, officials said.
"This will be the first of a number of repatriations into RAF Brize Norton," the British Foreign Office said in a statement.
The remains of the three Irish victims were also set to be flown home Wednesday.
Friday's death toll was the worst loss of life for Britain in a jihadist attack since the July 2005 bombings in London.
Cameron has promised to back a full investigation, calling for "a response at home and abroad" to violent Islamic fundamentalism.
British police have also sent forensic experts to Tunisia to help local teams probing the attack.
The 25 British tourists who were wounded have already been flown home, while 4,000 terrified holidaymakers were repatriated at the weekend. Another 1,900 were due to return home in the coming days.
The gunman, who witnesses say deliberately targeted tourists at the beach resort, had received weapons training from jihadists in chaos-wracked Libya, a top official said Tuesday.
Secretary of state for security Rafik Chelli told AFP that Rezgui had been in Libya at the same time as the two men behind the Bardo museum attack.
"It is confirmed that he (Rezgui) went to Libya illegally. He was trained in Sabratha (west of Tripoli)," Chelli said.
"They were away at the same time... In Sabratha, there is only one camp that trains young Tunisians," he said, although he could not confirm whether all three jihadists had trained together.