John Kerry Traveling to Paris for Talks on Extremist Violence

Obama administration faced criticism for not sending a senior official to rally.

As for criticism about the lack of a senior official at Sunday's March, Kerry said, "I really think that this is sort of quibbling a little bit in the sense that our Assistant Secretary of State Victoria Nuland was there and marched, our ambassador was there and marched, many people from the embassy were there and marched."

French officials say about 1.3 million people huddled in the windy streets, some appearing solemn, some upbeat, marching with French flags and "Je suis Charlie" – "I am Charlie" – signs. Some sang and clapped, and portions of the crowd spontaneously burst into applause as they marched.

It was the largest demonstration in French history, according to officials.

The march was a response to the massacre at the offices of Charlie Hebdo, a satirical weekly newspaper, and a subsequent pair of hostage-takings Friday, one of which involved the suspected gunmen. Seventeen people were killed during the three days of violence.

French police say they took extra precautions during the march, with more than 2,000 officers in the area and another 2,000 officers and 1,000 soldiers stationed throughout Paris.

"We have to consider the threat that we are facing,” he said. “You have in Europe thousands of young radicals – thousands of them – and of course, we are democracies and you don't arrest somebody because of his ideas.”

The Associated Press contributed to this report.