WASHINGTON, April 13  -- Can U.S. President Barack Obamaautomatically back Hillary Clinton's presidential bid? The White Housesaid "no" on Monday, despite that Obama's glowing words are still ringing.

"The president has not offered up any sort of endorsement at this point," White House spokesman Josh Earnest said, marking a step back to the tradition that sitting presidents do not publicly weigh in on selection of their party's next nominee.

During a visit to Panama on Saturday, Obama drummed up support for Clinton, saying "I think she would be an excellent president."

He described Clinton, who released a campaign video on Sunday announcing her 2016 presidential run, as "a formidable candidate," "a great supporter," "an outstanding secretary of state" and a friend.

The White House, however, clarified that "there are other people who are friends of president, who may at some point decide to get into the race."

Who are competing for Obama's "friendship?" They might turn out to be other Democratic candidates, including U.S. Vice President Joe Biden, former Maryland Governor Martin O'Malley and former Senator Jim Webb from Virginia, according to local media.

So, can Clinton receive Obama's official endorsement? She may have to wait, according to the White House, until "voters across the country have decided who the Democratic nominees should be."