Secretary of State Colin Powell (search) lamented the Palestinian suicide bombings in an Israeli shopping plaza and at a bus stop and said the Bush administration would continue to push for a peace accord between Israel and the Palestinian Authority.

But Powell also said "we will never get there so long as people continue to participate in terrorist activities, and we see the response to terrorist activities, which are necessary for self-defense."

Powell's statement to a Seeds of Peace (search) gathering of Israeli and Arab children at the State Department did not single out any group for Tuesday's bombings. Nor did it assign responsibility to any Palestinian organization, even though Hamas (search) claimed responsibility for the West Bank blast and a group linked to the Palestinian Authority for the other.

It was the first open violation of the cease-fire that Hamas, , listed as a terror group by the State Department, declared June 29 at the behest of Palestinian Prime Minister Mahmoud Abbas.

The Al Aqsa Martyrs Brigade (search), linked to Yasser Arafat's Fatah movement, claimed responsibility for one of the attacks.

The Brigade is a key part of the Palestinian Authority, which Arafat heads and of which Abbas is prime minister.

The two bombings raised new doubt about the fate of the truce and about Abbas' influence with Palestinian extremists. The U.S.-backed roadmap for peace calls for dismantling the terrorist structure on the West Bank and in Gaza.

Powell called the bombings "tragic news" and said innocent people lost their lives at the hands of people "who are not for the cause of peace." In fact, he said, they were trying to destroy the dreams of Israelis and Palestinians alike.

He said the United States and the United Nations, the European Union and Russia, which jointly produced the road map and its pledge to establish a Palestinian state in 2005, would do everything they could to move forward toward peace. The same, he said, was true of Prime Minister Ariel Sharon of Israel, Abbas and and Arab leaders.

"We owe it to you," Powell told the children in the audience. "We owe it to you to give you a better world."

He said that goal would be reached in the not-too-distant future. "I will have retired and gone on to something else. Others will have retired or gone elsewhere. Gone to their maker," Powell said.

In Jerusalem, Sharon warned that he would not move forward with the already troubled U.S.-backed peace plan "if terrorism doesn't cease completely."