Secretary of State Colin Powell is preparing to leave Washington late Friday for his first talks with Israeli and Palestinian leaders in the region in more than a year. Mr. Powell will press for action on the international "road map" that aims for a settlement of the Middle East conflict within three years.

The Powell mission comes against a background of optimism in Washington that changed circumstances, including the seating of a reform-minded Palestinian cabinet headed by new Prime Minister Mahmoud Abbas, have enhanced prospects for a settlement.

That was reflected in comments by President Bush Thursday at a White House meeting with the Emir of Qatar, Sheikh Hamad Bin Khalifa al-Thani.

"Of course we're going to make progress. Yes, we'll make progress. Absolutely. And the reason why we'll make progress is that the Palestinian Authority has now got a leader, in the Prime Minister, who has renounced violence. And he's said he wants to work with us to make the area more secure," he said. "He understands what we know, that a peace process will proceed if and when there is a concerted effort to fight violence."

Jointly developed by the United States, Russia, the European Union and the United Nations, the road map, handed to the parties April 30, calls for corresponding security and political steps by the two sides leading to full Palestinian statehood and Arab-wide recognition of Israel by the end of 2005.

Mr. Powell, who paid a brief visit to Syria and Lebanon last week, is due to meet Israeli Prime Minister Ariel Sharon in Jerusalem and Mr. Abbas in the West Bank town of Ramallah Sunday in what will be the first such talks in the region since a trip in April of last year.

His aim will be persuade both sides to take initial confidence-building steps to open the way for implementation of the "road map."

But the run-up to his visit has been marred by continuing violence, including on Thursday an Israeli helicopter attack in Gaza that killed an official of the radical Palestinian group Hamas, and a Palestinian suicide car bombing aimed at Israeli troops in Gaza.

State Department spokesman Richard Boucher said the incidents underscore the need for the parties to take practical steps to begin moving on the path of the road map, security measures by the Palestinians and action by Israel to ease conditions of life for ordinary Palestinians.

Under questioning, he said the continued practice of "targeted killings" of Palestinian militants by Israeli forces is not conducive to U.S. peace efforts.

"Our position on targeted killings has been and remains that they undermine the efforts to achieve peace," he said. "They aggravate the situation in the region. And they do not contribute to progress on Palestinian civil and security reform, all goals that we are trying to achieve. We've also made clear that Israel does have a right to self-defense, and there can be no excuse for the violence and terror that's been directed against the Israeli people."

Mr. Boucher said the United States has urged Israel to consider the consequences of its military action in Palestinian areas, and to take all appropriate measures to prevent casualties among innocent people, and damage to the civilian infrastructure.

After his meetings in Jerusalem and Ramallah Sunday, Mr. Powell will brief leaders in Egypt, Jordan and Saudi Arabia before completing his mission with stops in Europe. The dialogue on the road map will continue May 20 when Prime Minister Sharon meets President Bush at the White House.