The Palestinian groups Hamas and Islamic Jihad have called off what was left of the ceasefire with Israel.

The announcement came after Israel assassinated a top Hamas leader and two others in Gaza City yesterday.

The Los Angeles Times described the assassinated leader, Abu Shanab, as the chief political strategist of Hamas. He had been acting as the liaison between Hamas and Palestinian Prime Minister Mahmoud Abbas on peace negotiations.

Abbas called the airstrike a “ugly crime.” U.N. Secretary-General Kofi Annan condemned the airstrike as an extrajudicial killing and urged the Israeli government to show restraint.

The assassination came two days after a Palestinian suicide bomber killed 20 aboard a Jerusalem. Among the dead were five children. An additional 100 were injured in the deadliest Palestinian bombing in over three years.

In Gaza thousands of Palestinians took to the streets to mourn the death of Shanab. Many called for Abbas to step down.

A statement from Hamas urged “all our cells of fighters in Palestine to strike in every corner of the Jewish state.”

Secretary of State Colin Powell warned Israel and the Palestinian leadership to preserve the road map to peace.

Powell said, “The end of the road map is a cliff that both sides will fall off of. I believe both parties understand that a way has to be found to go forward. The alternative is what? Just more death and destruction?”

Israeli incursions into the West Bank and Gaza are continuing. Israeli tanks are reported to be in Jenin and Nablus. At least a dozen Palestinians have been detained. The main highways in Gaza have been closed splitting the area in three.