PARIS — More than a million people, including world leaders, marched in the streets of Paris to express their support for victims of last week's attacks and signal their disgust for the perpetrators — and a total of 3.7 million took part in rallies throughout France, officials said.
Crowds packed the entire two-mile march route from Paris' Place de la Republique to Place de la Nation, chanting "Vive la France" and "Qui vous etes? Charlie!" — "Who are you? Charlie!" — in reference to the massacre at the satirical magazine that left 12 dead on Wednesday. The demonstrators clapped, chanted and held posters and flags, including the French and Israeli ones.
The march was led by the historic sight of French President Francois Hollande linked arm-in-arm with Germany's Angela Merkel, Britain's David Cameron, Israel's Benjamin Netanyahu, Palestinian President Mahmoud Abbas and other world leaders in a show of solidarity against terror. More than 40 foreign leaders were expected to attend.
"Today, Paris is the capital of the world," said Hollande in a statement. “Our entire country will rise up toward something better."
The crowds spilled over the official planned march route, making a precise count of demonstrators impossible, according to the French Interior Ministry. But early on, the Ministry, which called the rally "unprecedented," estimated that at least 1.2 million people attended, making the gathering the largest in France's history.
And another 2.5 million people marched simultaneously in other parts of the country.
Dozens of sniffer dogs checked those who gathered in Paris, a sign of the heightened security in the wake of deadly attacks on the magazine that published satirical cartoons of Muslim Prophet Muhammad and on a kosher supermarket.
France is on the highest level of alert following the three days of violence that left 17 people dead, along with three gunmen. Security has been stepped up in France since the first deadly assault on Charlie Hebdo on Wednesday.
France's interior minister said "exceptional measures" will be taken to ensure security for the rally, from sweeping rooftops and gutters to posting snipers on the rooftops of Paris.
Some 2,000 police and 1,350 soldiers were providing security for the march and at sensitive sites in the city, Interior Minister Bernard Cazeneuv said. There will be 150 plainclothes police protecting the public figures on hand and doing surveillance.
The rally "must show the power, the dignity of the French people who will be shouting out of love of freedom and tolerance," Prime Minister Manuel Valls has said.
"Journalists were killed because they defended freedom. Policemen were killed because they were protecting you. Jews were killed because they were Jewish," he said. "The indignation must be absolute and total — not for three days only, but permanently."
Restaurant worker Ashley Lenglet admitted that she was very afraid, but said showed up to express her sympathy for those slain in the attacks, which have reverberated throughout France and around the world.
"I'm scared for what going to happen in France, for the future and for the future of my children," said the 20-year-old in the Place de la Republique, where the rally was set to start at 3 p.m. (10 a.m. ET). "But we'll fight and we are here to show the people who want to hurt that we are still here and we are in solidarity."
Khadeja Chouraki, 19, feared for her safety during the march, particularly because the sign she was carrying declared, "je suis francaise, muselman et charlie" — "I am French, Muslim and I am Charlie." Chouraki expressed the sentiment of many Muslims in the wake of the attacks, saying that the terrorists are "murderers — not Muslims."
Khadeja, who is also a cartoonist, said she wanted to express that the extremist attacks had nothing to do with Islam. "I wanted to show that we are not okay with what happened," she said.
The silent march 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.
"Today we are all French citizens," said U.S. Attorney General Eric Holder, who traveled to Paris to discuss the attacks and threats of foreign fighters.
Rallies were also planned in other areas of the French capital, as well as in London, Madrid, New York, Cairo, Sydney, Stockholm and Tokyo.
"Journalists were killed because they defended freedom. Policemen were killed because they were protecting you. Jews were killed because they were Jewish," he said. "The indignation must be absolute and total — not for three days only, but permanently."
Police were still searching for a fourth suspect in the attacks that horrified the world. Hayat Boumeddiene is described as the common-law wife of Amedy Coulibaly, who police believe killed a French policewoman Thursday and killed four hostages at a supermarket Friday before he was shot dead by police who stormed the grocery.
Police have said she is an accomplice in the killing of the policewoman, and she is believed to be armed.
Police were still searching for a fourth suspect in the attacks that horrified the world. Hayat Boumeddiene is described as the common-law wife of Amedy Coulibaly, who police believe killed a French policewoman Thursday and killed four hostages at a supermarket Friday before he was shot dead by police who stormed the grocery.
Police have said she is an accomplice in the killing of the policewoman, and she is believed to be armed.
But there were reports that Boumeddiene may be in Syria. French media reported that she already left France last week — taking a flight from Madrid to Syria via Turkey. Surveillance images "are certain" to be of Boumeddiene, reported French newspaper Le Figaro on Saturday, citing a police source. NBC News could not immediately verify those reports. The prosecutor's office declined to comment on her whereabouts.
Meanwhile, crowds remained at Place de la Nation past 8 p.m. (2:00 p.m. ET) lighting candles and chanting, as one message resonated throughout: "We march, we march, we march. We are not scared of terrorists!"
Elisha Fieldstadt, Phil Helsel and F. Brinley Bruton contributed to this report. Reuters and The Associated Press also contributed.