Arafat released a statement shortly after the al-Aqsa Martyrs Brigade, linked to his own Fatah movement, claimed responsibility for Wednesday's suicide bombing in Jerusalem that killed six Israelis. Nineteen were killed in Tuesday's attack on a bus.
"I have to tell you frankly to stop as soon as possible these attacks that all of us have severely condemned," Arafat said in the statement, written in Arabic.
He said the attacks have no place in the Palestinian people's legitimate struggle against Israeli occupation. Arafat added that targeting civilians, whether they are Israelis or Palestinians "is an act condemned by me, the Palestinian leadership and the international community."
Arafat's statement went on, "Those attacks are becoming the strongest excuse for the Israeli government to continue its military plans and actions and to kill tens of thousands of our innocent people."
"Zionists leave this land. We will not stop our operations as long as their remains an occupier on our land," the al-Aqsa statement said.
In response, Israeli helicopter gunships fired on targets in Gaza. The Israel Defense Forces said its helicopters attacked buildings used to produce weapons.
Palestinian sources said 13 people were wounded in the attack.
In Washington, President George W. Bush's policy speech laying out his vision for the Middle East was postponed because of the latest suicide bombing, White House spokesman Ari Fleischer said.