– The White House acknowledged Monday that it blundered in not sending a prominent administration official to Sunday's giant rally in Paris in support of free speech, making a rare admission of a mistake but offering little insight.

Spokesman Josh Earnest told reporters that the White House regretted sending only the U.S. ambassador to France and an assistant secretary of state to the march, which drew more than 40 world leaders and about 1.5 million people to show support for victims of last week's terrorist attacks in which gunmen opened fire at a newspaper and a kosher market, killing more than a dozen altogether.

"It's fair to say that we should have sent someone with a higher profile to be there," Earnest said, adding that the decision should not raise doubts that the administration stands "shoulder-to-shoulder with our allies in France."

Critics quickly blasted the White House for leaving the U.S. underrepresented at the event, and allies expressed bewilderment at the missed opportunity. A photograph of the world leaders — arms linked in solidarity — splashed across front pages and TV around the world. Among those present were French President Francois Hollande, German Chancellor Angela Merkel, British Prime Minster David Cameron, Israel Prime Minister Benjamin Netanyahu and Palestinian Authority President Mahmoud Abbas.

White House officials would not describe how they decided to essentially sit the event out. The decision was not made by Obama, Earnest said, but the spokesman would not say who made it.

The president was at the White House all day Sunday, with no public events on his schedule. Earnest declined to comment on how Obama spent his day. Potential surrogates had little explanation. Vice President Joe Biden spent the day at his home in Delaware. Attorney General Eric Holder traveled to Paris to attend a series of meetings with French officials on counterterrorism, but did not attend the rally.

Secretary of State John Kerry, perhaps the mostly likely replacement, had the clearest scheduling conflict. Kerry was in India and due for a surprise trip to Pakistan.

That left Jane Hartley, the U.S. ambassador to France, and Victoria Nuland, the assistant secretary of state for Europe, as the highest-ranking officials at the march.

Although the White House acknowledged a higher-level official should have attended, it did not necessarily concede the president should have been the one to make the trip.

Earnest suggested security was a factor.