An Israeli security operation against the militant group Hamas "will probably not end within several days," Defense Minister Moshe Ya'alon said Tuesday.
The development appeared to confirm fears that the conflict would continue to escalate.
"We will not tolerate rocket fire and we are prepared to expand the operation and to exact a heavy toll on Hamas," he said.
Overnight, Israel ramped up its airstrikes on Hamas in Gaza.
The Israeli military's Operation Protective Edge against Hamas has entered a "substantial phase," with airstrikes hitting around 50 targets, including militant houses and military compounds, Israeli military spokesman Lt. Col. Peter Lerner told CNN.
"We are determined to restore a state of security," he said.
Hamas security sources reported at least 60 Israeli airstrikes across Gaza, including from F-16s, Apache helicopters and drones. The sources said at least 10 people were wounded.
Palestinian Authority President Mahmoud Abbas called on Israel to immediately stop its strikes, warning the operation would drag the region into instability.
Abbas said a truce was needed to "spare the innocent from mass destruction."
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