US Secretary of State John Kerry will travel to France after the White House was criticised for not sending a senior official to the Paris unity rally.
Mr Kerry defended his absence, citing prior commitments and saying the US relationship with France “is not about one day or one particular moment”.
The rally, which follows three terror attacks, was attended by an estimated 1.6m people and some 40 world leaders.
The US ambassador to France was the highest ranking US official attending.
Seventeen people died in attacks in Paris at a satirical magazine, another on a police officer, and a third at a kosher supermarket.
Mr Kerry told reporters in India he will visit France to reaffirm US solidarity with France, which he called America’s oldest ally.
A fluent French speaker, he has visited the country 17 times since becoming Secretary of State.
He and Mr Obama were criticised by US media over the weekend for not attending the rally.
Among those linking arms in a symbolic gesture at the march was UK Prime Minister David Cameron, German Chancellor Angela Merkel, Israeli Prime Minister Benjamin Netanyahua and Palestinian President Mahmoud Abbas.
US Attorney General Eric Holder, in Paris for an anti-terror summit, did not attend the march because he was giving media interviews.
World leaders attend the “Marche Republicaine” in Paris, France 11 January 2015 About 40 world leaders and dignitaries marched arm in arm
White House officials told CBS News Mr Obama did not attend because his security would have interfered with the huge crowds.
Mr Kerry was visiting India, for an international development trip, and Pakistan to meet Prime Minister Nawaz Sharif.
“I would have personally very much wanted to have been there,” Mr Kerry said, but said “it is important to keep these kinds of commitments”.
Mr Kerry said US officials, including himself and President Barack Obama, had been “deeply engaged” with French authorities since the first attack and had offered intelligence assistance.
“I want to emphasise that the relationship with France is not about one day or one particular moment,” Mr Kerry said.
“It is an ongoing long-time relationship that is deeply, deeply based in the shared values, and particularly the commitment that we share to freedom of expression.”
Mr Kerry is expected to arrive in Paris later this week.
Meanwhile, the White House announced there were would be an international summit in Washington in February on countering violent extremism.