Secretary of State Colin Powell on Sunday blamed the abrupt departure of U.S. envoy Anthony Zinni from the Middle East on Palestinian terrorist violence.

Zinni had been in the region for three weeks with the goal of brokering a cease-fire deal, but left Saturday and flew back to Washington.

"We sent General Zinni over to try to get that dialogue going, and all of that was blown up by these terrorist organizations on the Palestinian side," Powell said on Fox News Sunday.

Continued eruptions of violence stalled early progress in the peace process made by Zinni, who was told Saturday to return to Washington, according to Powell. During Zinni's visit, more than 100 people —  about 60 Palestinians and 40 Israelis —  were killed.

"Hamas, a terrorist organization, started killing innocent civilians with car bombs in Jerusalem, Haifa and elsewhere. And they attacked this process; they attacked innocent Israelis," Powell told Fox News. "But even more fundamentally and troubling, they attacked Yasser Arafat and his authority to lead the Palestinian people toward a cease-fire and a process of peace."

Zinni's mission was accompanied by a fresh surge in attacks by Islamic militants on Israelis, followed by Israeli reprisals. Despite all the deaths and unrest, Powell said optimism was still in order.

"Right now, I don't want to lose hope," he said. "The Zinni mission has not failed. The parties have failed. Zinni went to help them, and they were not ready ... to be helped at this point."

Zinni is to consult with President Bush and Powell about the situation — meetings that Powell said always were planned.

"We are not disengaging and his mission is not ended," Powell said on NBC's Meet the Press.  "He is still our special envoy for that purpose. And he will do whatever it takes."

Powell said Zinni will go back to the Gaza Strip region when there is a "real reason."

He called on the Palestinian leader to end the violence and said those responsible for it "are attacking Mr. Arafat just as surely as they are attacking the people of Israel or the state of Israel, and Mr. Arafat has to act against them."

Though he said he finds fault with both sides, Powell underscored what he characterized as the Palestinians' inability to get a handle on the violence.

"If violence gets under control, gets down to zero or as near zero as you can make it ... then I think you will get a response from the Israeli side and we can start to move forward," Powell said.

Asked about Arafat's future if he is unable to crack down, Powell said: "I think the consequence for him is that he will slowly lose authority within the region." The United States, he said, "will be examining all of our options of how we deal with him."

Zinni's efforts were complicated when the Israeli government said Wednesday it was severing contacts with Arafat. Zinni then suspended talks with the two sides to appeal directly to Arab leaders to intervene with Arafat.

The Associated Press contributed to this report.