British police are to step up security in Jewish areas of the country after yesterday's attack at a French kosher supermarket, a Jewish community body said on Friday.

The Community Security Trust (CST), which provides security advice to Britain's estimated 260,000 Jews, said police in London and Manchester had agreed to increase patrols at synagogues and other venues over the next days.

"There is currently no known link to the UK, but CST is in continuing contact with police and government, and there will be increased policing in Jewish neighbourhoods for this weekend's Sabbath," the trust said on its website.

Last July, the CST said anti-Semitic incidents in Britain had risen amid fighting between Israeli forces and Palestinians in Gaza.

The two brothers suspected of a bloody attack on the offices of French satirical newspaper Charlie Hebdo were killed when police stormed their hideout on Friday, while the siege at the Hyper Cache supermarket in Vincennes ended with the deaths of four hostages and the attacker.

The violent end to the simultaneous stand-offs followed a police operation of unprecedented scale as France tackled one of the worst threats to its internal security in decades. The heavy loss of life over three consecutive days also risked fuelling anti-immigrant voices in the country and elsewhere in the West.

News footage of the Hyper Cacher kosher supermarket in the Vincennes district showed dozens of heavily armed police officers massed outside of two entrances. The assault began with gunfire and a loud explosion at the door, after which hostages were rushed out.

Reuters photographs taken from long distance showed a man holding an infant and looking distressed being herded into an ambulance by police. Others were carried in on stretchers.

The violence raised questions about surveillance of radicals, far-right politics, religion and censorship in a land struggling to integrate part of its five million-strong Muslim community, the largest in the European Union.

Additional reporting by Reuters.