Islamic State has claimed responsibility for the Paris attacks, as French President Francois Hollande pledged a “pitiless” response to terrorism.

 police officer stands guard outside the Bataclan concert hall, Saturday, Nov. 14, 2015

police officer stands guard outside the Bataclan concert hall, Saturday, Nov. 14, 2015 Image by (AP Photo/Amr Nabil)

IS made the claim in an online statement as Mr Hollande vowed to strike back after the worst attacks in France since the Second World War

Mr Hollande said after an emergency security meeting that the death toll in Paris had risen to 127 in a string of near-simultaneous attacks which he said were an “act of war” orchestrated by IS.

He declared three days of national mourning and put the nation’s security at its highest level after the assault on a concert hall, sports stadium and cafes.

French President Francois Hollande speaks at the Elysee Palace in Paris, Saturday, Nov. 14, 2015, following a series of coordinated attacks in and around Paris late Friday which left more than 120 people dead.

French President Francois Hollande speaks at the Elysee Palace in Paris, Saturday, Nov. 14, 2015, following a series of coordinated attacks in and around Paris late Friday which left more than 120 people dead. Image by (Stephane de Sakutin/Pool Photo via AP)

Mr Hollande has also declared a state of emergency – the first such move in a decade – and ordered 1,500 additional troops to be deployed to guard official buildings and religious sites, while controls have been re-imposed at the country’s borders.

He said the attacks were “committed by a terrorist army, the Islamic State group, a jihadist army, against France, against the values that we defend everywhere in the world, against what we are: a free country that means something to the whole planet”.

Mr Hollande added that France “will be merciless toward the barbarians of Islamic State group”, and “will act by all means anywhere, inside or outside the country”.

France is already bombing IS targets in Syria and Iraq as part of the US-led coalition, and has troops fighting extremists in Africa.

Police are hunting for potential accomplices to eight attackers who were killed as at least six sites in Paris were attacked in rapid succession.

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