Hundreds of thousands of people poured through the streets of Paris on Sunday afternoon, heading towards the Place de la Republique in an unprecedented show of solidarity after the week's terrorist attacks in France.

The march was led by families of the victims as well as dozens of world leaders, who included French President Francois Hollande flanked by German Chancellor Angela Merkel and Malian President Ibrahim Boubacar Keita. National leaders, like many of the other marchers, walked arm in arm.

Giant letters attached to a statue in the Place de la Republique spelt out the word "Pourquoi?" (Why?) with sections in the crowd singing the "La Marseillaise" national anthem.

Former French Junior Minister for Urban Affairs Francois Lamy - the lawmaker tasked by the ruling Socialist Party with organizing the rally - said he had been told the number would be between 1.3 and 1.5 million.

The French Interior Ministry said Sunday that the scope of the march in Paris was "unprecedented."

Police snipers poised

Some 2,200 police and soldiers were on patrol in Paris to protect marchers, with police snipers on rooftops and plain-clothed officers mingling in the crowds.

A total of 17 people died in three days of violence that began on Wednesday with the murders of 10 people at the Charlie Hebdo office. A security guard and police officer were shot dead outside the magazine's office.

Another police officer was killed on Thursday, as were four hostages taken during a siege at a kosher supermarket on Friday.

"Charlie! Charlie!" was one of the rallying cries at the Paris march, held in memory of the journalists gunned down at the Charlie Hebdo satirical magazine's offices on Wednesday.

'Capital of the world'

Palestinian President Mahmoud Abbas, Israeli Prime Minister Benjamin Netanyahu and British Prime Minister David Cameron were among the many other world leaders from Africa, Europe and the Middle East who traveled to the French capital.

"Paris is the capital of the world today," said President Hollande, a few minutes before welcoming the leaders. "Our entire country will rise up toward something better."

Rallies were also organized in London, Brussels, Madrid and New York - all attacked by al Qaeda-linked extremists - as well as Cairo, Sydney, Stockholm and Tokyo.

Some 18,000 people - many carrying pencils and flowers - gathered next to the iconic Brandenburg Gate in Berlin, in front of the French embassy. As well as signs reading "Je juis Charlie," (I am Charlie) some read "Je suis Juif" (I am a Jew).

The Charlie Hebdo killers - Said and Cherif Kouachi - and grocery hostage taker Amedy Coulibaly died when police launched simultaneous raids on the two sites where they were holed up.

rc/sms (AFP, AP)