David Cameron has said the West must stop "the poisoning of young minds" by Islamic State and other extremists.
The Prime Minister said he had spoken to Francois Hollande to offer his support after the attack near Lyon and would also speak to the Tunisian government following the attack there to offer "our solidarity in fighting this evil of terrorism".
"This is a threat that faces all of us," Cameron said. "These events have taken place today in Tunisia and in France but they can happen anywhere. We all face this threat."
"The people who do these things, they sometimes claim they do it in the name of Islam. They don't. Islam is a religion of peace," he said.
"They do it in the name of a twisted and perverted ideology that we have to confront with everything that we have."
Stories continue to emerge of the heroism and compassion of Tunisians who tried to help in the wake of the Sousse attack.
Seifeddine Rezgui was halfway through a Masters degree and took exams at the Institute for Applied Science and Technology before the attack.
As details of the dead continue to surface, James Jordan met Mohamed Sabhi, who ran towards the carnage to shepherd tourists to safety.