Britain will provide intelligence and counter-terrorism assets to help an international effort to track down and dismantle the terror network responsible for last week's attack on an Algerian natural gas plant, Prime Minister David Cameron told MPs.
Mr Cameron said that the world was involved in a "generational struggle" against al Qaida-inspired Islamist terrorism in North Africa, and vowed to show "iron resolve" in his response to the challenge.
He stressed that the international community's action must be "tough, intelligent and patient" and combine a strong security response with political moves to tackle instability and resolve grievances as well as a long-term drive to counter the "poisonous" ideology of violent extremism.
Mr Cameron confirmed that Britain will provide troops to a French-led EU mission to train the Malian military to take on Islamist militants who have taken over the north of the country. The mission, due to deploy in February or March, is expected to include around 250 trainers and 250 force protection troops and Mr Cameron said that the British contribution would number "in the tens, not the hundreds", with aides saying it would be at the lower end of that range.
The PM also revealed that the National Security Council will tomorrow discuss what further transport and surveillance assistance Britain can offer to French troops who are fighting rebels in northern Mali.
The meeting is expected to approve the continued use of RAF C17 airlift planes to move French troops and hardware. He promised to put the issue of terrorism "right at the top of the agenda" for Britain's presidency of the G8 group of rich nations in 2013.
After the end of the terror siege at the In Amenas desert complex, which is believed to have claimed the lives of six British nationals and one foreign-born UK resident, Mr Cameron said that the immediate priority was to identify and repatriate the bodies of those who died.
Three of the Britons killed have been named as 46-year-old security expert Paul Morgan, systems supervisor Garry Barlow, 49, from Liverpool, and 59-year-old planning manager Kenneth Whiteside, from Glenrothes, Fife. Colombian BP executive Carlos Estrada, who lived in London, is also believed to have died.
The Algerian authorities today said that 37 foreign hostages were confirmed dead at the site - part-operated by BP - and a further five are missing. Some 29 of the hostage-takers died, while three were captured by Algerian troops.
Labour leader Ed Miliband offered the Government his party's "full support" in bringing to justice those responsible for what he termed "pre-meditated, cold-blooded murder of the most brutal kind".