President Obama and Israeli Prime Minister Benjamin Netanyahu spoke by phone on Sunday as a cease-fire with Hamas broke apart.
Obama reiterated his "strong condemnation" of rocket and tunnel attacks against Israel by the militant group Hamas, but also expressed "growing concern" about the rising number of Palestinian civilian deaths in Gaza.
Negotiations to extend a 12-hour truce broke down over the weekend. Israel says it offered to extend the cease-fire for another 24 hours, only to see new rocket fire from Gaza. Israel then resumed its own military actions in Gaza.
"Hamas has broken five cease-fires that we accepted," Netanyahu said on Fox News Sunday. "They rejected all of them, violated all of them, including two humanitarian cease-fires in the last 24 hours."
On the call with Netanyahu, Obama stressed the need to enact a "sustainable cease-fire" that both "allows Palestinians in Gaza to lead normal lives, and addresses Gaza's long-term development and economic needs while strengthening the Palestinian Authority."
Any lasting solution to the ongoing conflict would only occur with the disarmament of terrorist groups and demilitarization of Gaza, Obama said.