London (AFP) - Prime Minister David Cameron said Britain would review security plans after attacks in Paris in which at least 128 people were killed, warning that Britain faced "the same threat".
"In the light of last night's attacks, we will of course review our plans and make sure we learn any appropriate lessons," Mr Cameron said after an emergency cabinet meeting in Downing Street.
"It is clear that the threat from Isil (IS) is evolving. Last night's attacks suggest a new degree of planning and coordination and a greater ambition for mass casualty attacks," he said.
"We in the UK face the same threat," he added.
Mr Cameron also warned that Britons should expect "a number" of the victims in Paris to British citizens.
He condemned the attackers as "brutal and callous murderers", adding: "We will redouble our efforts to wipe out this poisonous, extremist ideology".
Britain held its biggest-ever counter-terror drill in June, involving 1,000 police officers, special forces, ambulance and fire crews in a simulation of a "marauding terrorist attack".
The exercise came shortly after a spree killing on the Tunisian resort of Sousse on June 26 in which 38 people were killed - 30 of them Britons.
It also came ahead of the 10th anniversary commemorations of the July 7, 2005 attacks on London's transport system, when four suicide bombers killed 52 people.