Obama also pointed to the next 48 hours "to see what kind of progress we can make."
Members of the U.S. Congress, which overwhelmingly supports Israel, criticized Egypt and Turkey for not doing enough to intervene. They said all eyes were on Morsi, Egypt's first civilian and freely elected leader.
"Egypt, watch what you do and how you do it," said Sen. Sen. Lindsey Graham, R-S.C., in an interview on NBC's "Meet the Press." ''You're teetering with the Congress on having your aid cut off if you keep inciting violence between the Israelis and the Palestinians."
In a separate interview on ABC's "This Week," Sen. Carl Levin, chairman of the Armed Services Committee, called Egypt's response to the crisis "pretty weak" so far.
"I think that they're going to have to take some very serious steps diplomatically to make it clear to Hamas that they're going to lose support in the Arab world if they continue these rocket attacks on Israel," said Levin, D-Mich.
Lawmakers also blamed Iran for arming Hamas militants, and questioned Egypt's role in that.
"My guess is there has to be some tacit involvement in Egypt and the border or these things wouldn't be getting in to Gaza," said Rep. C.A. "Dutch" Ruppersberger of Maryland, the top Democrat on the House Intelligence Committee.
Sen. Joseph Lieberman, I-Conn., said he thinks the threat of a ground war is overblown.
"I don't think the Israelis really want a ground war," he told "Fox News Sunday." ''They'll go into Gaza if they feel they need to, to eliminate the remainder of the missiles. ... So really, the decision is up to Hamas, as to whether there will be a ground invasion of Gaza or not."
Flaherty reported from Washington. Associated Press writer Gregory Katz in London contributed to this report.