World leaders gather for Paris march honouring attack victims

French President Francois Hollande is surrounded by head of states including (L to R) Israel's Prime Minister Benjamin Netanyahu, Mali's President Ibrahim Boubacar Keita, Germany's Chancellor Angela Merkel, European Council President Donald Tusk and Palestinian President Mahmoud Abbas as they attend the solidarity march (Marche Republicaine) in the streets of Paris, January 11, 2015. [Photo/Agencies]

French President Francois Hollande observe a minute of silence surrounded by heads of state including (LtoR) Israel's Prime Minister Benjamin Netanyahu, Mali's President Ibrahim Boubacar Keita, Germany's Chancellor Angela Merkel, European Council President Donald Tusk, Palestinian President Mahmoud Abbas and King Abdullah of Jordan and Queen Rania Al Abdullah as they attend the solidarity march (Marche Republicaine) in the streets of Paris January 11, 2015. [Photo/Agencies]

PARIS - Dozens of world leaders joined hundreds of thousands of French citizens marching in Paris amid high security in an unpredecented tribute to victims of this week's Islamist militant attacks.

President Francois Hollande and leaders from Germany, Italy, Israel, Turkey, Britain and the Palestinian territories among others, moved off from the central Place de la Republique ahead of a sea of French and other flags. Giant letters attached to a statue in the square spelt out the word Pourquoi?" (Why?) and small groups sang the "La Marseillaise" national anthem.

Some 2,200 police and soldiers patrolled Paris streets to protect marchers from would-be attackers, with police snipers on rooftops and plain-clothes detectives mingling with the crowd. City sewers were searched ahead of the vigil and underground train stations around the march route are due to be closed down.

The silent march - which may prove the largest seen in modern times through Paris - reflects shock over the worst militant Islamist assault on a European city in nine years. For France, it raised questions of free speech, religion and security, and beyond French frontiers it exposed the vulnerability of states to urban attacks.

"Paris is today the capital of the world. Our entire country will rise up and show its best side," said Hollande in a statement.

Seventeen people, including journalists and police, were killed in three days of violence that began with a shooting attack on the satirical newspaper Charlie Hebdo on Wednesday and ended with a hostage-taking at a Jewish deli in which four hostages were killed.

Overnight, an illuminated sign on the Arc de Triomphe read: "Paris est Charlie" ("Paris is Charlie").

A video emerged featuring a man resembling the gunman killed in the kosher deli. He pledged allegiance to the Islamic State insurgent group. A French anti-terrorist police source confirmed it was the killer, Amedy Coulibaly, speaking before the action.