On the evening following Wednesday's gun attack at the satirical magazine Charlie Hebdo, Paris mayor Anne Hidalgo confirmed that the lights of the French capital's Eiffel Tower would be switched off at 8 p.m. local time (1900 GMT), as a vigil got underway at the Place de la Republique on the other side of the capital.

"Our city has been a refuge for writers, philosophers, journalists who were threatened for their ideas," Hidaglo told French paper Liberation. "There is no place in Paris for extremist ideas of any sort."

A mass commemorating the victims of the Paris attack was also held by Pope Francis on Thursday afternoon in Saint Martha's Chapel, opposite St Peter's Basilica in the Vatican.

"Let us pray in this mass, for the victims of this cruelty ... Let us also pray for the perpetrators of these cruel acts, so that the Lord might transform their hearts," he said.

'Stupidity will not win'

The satirical magazine, which was targeted in Wednesday's fatal attack, also announced on Thursday that a "survivors' issue" will be published next Wednesday.

Charlie Hebdo columnist Partrick Pelloux told AFP news agency that the the magazine had decided to continue publishing to show that "stupidity will not win."

Normally just 60,000 copies of the weekly magazine would be printed, only a half of which are usually sold. Following a wave of support to save Charlie Hebdo from bankruptcy, however, 1 million copies will be printed next Wednesday.

Copies of this week's issue have also been appearing on online auction websites with bids of over 70,000 euros ($82,400).

Manhunt

French officers continued on Thursday, however, to hunt down the two missing gunmen in the northeastern region of Picardy. A third suspect in the killing, 18-year-old Mourad Hamyd, turned himself in to police in the town of Charleville-Mezieres on Wednesday evening after learning he had been linked to the attacks.

Cherif Kouachi and his brother Said are thought to have been seen on Thursday morning at a gas station near the small town of Villers-Cotterets - 60 kilometers (38 miles) northeast of Paris.

Amid speculation that the attackers might be heading for Calais, the UK also increased its security at some ports and border entry points on Thursday.

Earlier on Thursday, a policewoman was shot dead in a separate incident in Paris. It remains unclear whether the shooting was linked to Wednesday's attack. Two men were later taken into custody.

ksb/msh (Reuters, AFP, AP, dpa)