President Obama, wiping away tears, said Friday that the nation's "hearts are broken" for the 20 children and at least six adults killed during a mass shooting at a Connecticut elementary earlier in the day, one of the deadliest shooting sprees in U.S. history.

"The majority of those who died today were children - beautiful, little kids between the ages of 5 and 10 years old," Obama, the father of two daughters, said at the White House. "They had their entire lives ahead of them - birthdays, graduations, weddings, kids of their own."

Citing a recent spate of mass shootings, from a temple in Wisconsin to a mall in Oregon to a movie theater in Colorado, Obama alluded to the possibility that he would seek additional controls on guns as he enters his second term.

"We're going to have to come together and take meaningful action to prevent more tragedies like this, regardless of the politics," he said.

Gun-control advocates have been pressing the president to impose more restrictions on guns - including a new ban on assault weapons - prior to Friday's shootings. And while they heard nothing specific from the president Friday, advocates said they welcomed Obama's call to action.

Police in Newtown, Conn., said a man, identified by numerous media outlets as Adam Lanza, opened fire inside Sandy Hook Elementary School, where his mother taught kindergarten, killing her, 20 students between the ages of 5 and 10, several other adults and then himself. Police said Lanza may also have killed his father in New Jersey before going to the Connecticut school.

Shortly before he spoke, Obama ordered that flags be flown at half-staff until sunset on Dec. 18.

Friday's mass killing was the second-deadliest in U.S. history, behind only the 2007 massacre at Virginia Tech in which 32 people died.

Obama concluded his brief remarks with an appeal for Americans to come together in the wake of tragedy.

"In the hard days to come, that community needs us to be at our best as Americans, and I will do everything in my power as president to help," he said. "Because while nothing can fill the space of a lost child or loved one, all of us can extend a hand to those in need, to remind them that we are there for them, that we are praying for them, that the love they felt for those they lost endures not just in their memories, but also in ours."