WASHINGTON (AP) — As world leaders linked arms and marched in defiance of terror attacks in Paris, there was one glaring absence: a high-level representative from the United States.

President Barack Obama spent the weekend at the White House. Vice President Joe Biden was in his hometown of Wilmington, Delaware. Secretary of State John Kerry was on a long-planned trip to India. Attorney General Eric Holder was in Paris attending a security summit, but did not make an appearance at the march on Sunday.

The Obama administration was instead represented by U.S. ambassador to France Jane Hartley.

That decision sparked criticism of the administration, including from Sen. Marco Rubio, R-Fla., who called it a mistake for the U.S. to not have higher level representation at a rally supporting the nation's oldest ally.

"Eric Holder was in Paris, and maybe John Kerry should have gone, or somebody else," Rubio said in an interview on CBS This Morning. "There's a plethora of people they could have sent. I think in hindsight I hope that they would have done it differently."

More than a million people walked the boulevards of Paris Sunday in what French officials called the largest demonstration in their country's history. The rally was aimed at showing unity following terror attacks by Islamic militants that left 17 people dead.

The procession was led by more than 40 world leaders, including Israeli Prime Minister Benjamin Netanyahu, Palestinian President Mahmoud Abbas, British Prime Minister David Cameron and German Chancellor Angela Merkel.

The White House has yet to explain why it decided to forgo high-level representation at the march. The president's overseas travel is usually planned well in advance given the enormous security apparatus that accompanies him. The vice president has a lighter security footprint and can sometimes travel overseas more quickly.

Asked about the criticism, Kerry said, "I really think that this is sort of quibbling a little bit." Still, the State Department announced that Kerry would be traveling to Paris this week to show solidarity with the French people.

The Justice Department sidestepped questions about why Holder didn't appear at the march despite being in Paris Sunday. Spokesman Brian Fallon noted that Holder had been with French officials during his trip and pledged "continued assistance to the French authorities as they conduct their investigation."

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