This post has been updated.
Israel and Hamas agreed late Monday to an Egyptian-sponsored 72-hour cease fire.
At a news conference Friday, Obama underscored Israel's right to defend itself and noted American support for the Iron Dome.
"And so, not only have we been supportive of Israel in its right to defend itself, but in very concrete terms -- for example, in support for the Iron Dome program that has intercepted rockets that are firing down on Israeli cities -- we've been trying to cooperate as much as we can to make sure that Israel is able to protect its citizens," Obama said.
An Israeli airstrike Sunday killed 10 people outside a U.N. school in Gaza, prompting some of the harshest American criticism of Israel since the conflict began.
State Department spokeswoman Jen Psaki said in a statement that “the United States is appalled by today’s disgraceful shelling” and urged Israel to do more to “avoid civilian casualties” and to protect U.N. facilities.
Before the cease-fire announcement Monday, White House Press Secretary Josh Earnest said the United States continues to push for a cease-fire and that it has expressed its concerns about the Israeli military living up "to their own standards" about protecting civilians.
"We do continue to believe that the violence in Gaza should end as soon as possible," Earnest said.