John Kerry Traveling to Paris for Talks on Extremist Violence

— -- Secretary of State John Kerry Monday said he will travel to Paris this week for talks on countering extremist violence, following sharp criticism of the Obama administration for not sending a senior official to Sunday's rally for unity in Paris that was attended by about 40 world leaders and more than a million people.

U.S. officials, including Kerry and President Barack Obama, had been "deeply engaged" with French authorities almost immediately after the first attack occurred and had offered intelligence assistance, he said at a news conference.

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."

"As everybody knows, I have been here in India for a prior planned event," he added. "I would have personally very much wanted to have been there but couldn't do so because of the commitment that I had here and it is important to keep these kinds of commitments."

An additional 10,000 troops will be deployed across France for added security, authorities confirmed to ABC News, while 4,700 police will be deployed at Jewish schools across the country, according to the interior ministry.

Sunday’s march was part of a “cry for freedom” to honor those killed in the recent terror attacks in Paris. The march began at the Place de la Republique, near the Charlie Hebdo offices where 12 people were killed Wednesday.

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.

It is "very likely" that the country will face more attempted terrorist attacks, Gerard Araud, the French ambassador to the United States, told ABC News.

"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.

Get real-time updates as this story unfolds. To start, just "star" this story in ABC News' phone app. Download ABC News for iPhone here or ABC News for Android here. To be notified about our live weekend digital reports, tap here.