President George Bush has directed Secretary of State Gen Colin Powell to go to the Middle East to revive attempts at a cease-fire.
"The storms of violence cannot go on," Mr Bush said. "Enough is enough."
Gen Powell is expected to go to the region next week to attempt to arrange an immediate cease-fire.
Until now the US has been pinning its hopes on a cease-fire and a return to peace talks on Middle East envoy Mr Anthony Zinni, whose latest mission was disrupted by a wave of suicide bombings.