The murder of two students stabbed and beaten to death by a crowd of youths in a matter of minutes in a poor suburb of Grenoble has shocked France and increased pressure on François Hollande to deal with long-running issues of crime, poverty and disaffected youths on deprived housing estates.

Kevin Noubissi and Sofiane Tadburt, both 21, were attacked in a park on Friday night for reasons that are still unclear, but local accounts suggested it was because one of their younger brothers had looked at someone "the wrong way" outside school. A crowd of around 12 young men, believed to include teenagers, hit the men with pick-axe handles, baseball bats, hammers and knives, taking two minutes to kill one, while the other died shortly after in hospital.

The Socialist interior minister, Manuel Valls, described it as a massacre.

Neighbours said the two men had a reputation as mediators in the suburbs of Grenoble, where crime, unemployment and rivalry between tower-blocks is rife.

One victim was a university student and son of a local paediatrician on the estate, the other was a friend from his childhood. The paediatrician, Aurélie Noubissi, said: "I've lost a child to an absurd death."

The case has sparked a change in Francois Hollande's reaction to high-profile crime. Until now, the Socialist president had not followed Nicolas Sarkozy's habit of personally travelling to the scene of crimes and murders and being filmed trying to reassure families. But in a televised visit on Monday night, Hollande arrived on the estate in Echirolles on Grenoble's outskirts to meet the victims' families and promise justice for an "odious crime".

One resident yelled down from her window to Hollande that violence was plaguing the area and authorities were failing to act. "They can't be allowed to have died for nothing." Hollande replied: "They won't have died for nothing, I'll be back."

Shortly after his visit, police arrested 10 people in an operation that was partly filmed and shown on rolling news channels. The police search for suspects continues. As locals prepared a march in memory of the men, the interior minister announced that the Villeneuve area where the attack took place would get more resources as a priority security area.

Hollande's visit sparked painful memories of Sarkozy's 2010 reaction to three nights of violent clashes between police and armed rioters in the same area of Grenoble's outskirts after police shot a robbery suspect in a chase. Sarkozy visited Grenoble and made one of his most criticised security speeches, pledging to strip foreign-born individuals of their French nationality if they attacked police or public officials.