Direct peace negotiations between Israel and the Palestinian Authority can be concluded within a year, U.S. special Mideast envoy George Mitchell said Tuesday, hours before the talks were set to begin in Washington.

U.S. President Barack Obama considers the possibility of achieving peace in the Middle East a top priority, Mitchell told reporters at a briefing.

Earlier Tuesday, about three hours after a deadly shooting attack in the West Bank that left four Israeli civilians dead, Prime Minister Benjamin Netanyahu arrived in Washington, where he was scheduled to meet U.S. Secretary of State Hillary Clinton later in the day.

Clinton launched the U.S. push for Mideast peace on Tuesday, holding one-on-one talks with Israeli and Palestinian leaders before they sit down on Thursday for direct negotiations.

Mitchell insisted that while the United States recognized that "there are many experienced and knowledgeable people who hold different view," when "it really comes to the end, what is best for the people of Israel and the Palestinian people, I believe strong and persuasive arguments can be made."

Remarking on the extent of U.S. participation in the actual talks, Mitchell said that "the United States will play an active and sustained role in the process, but that doesn’t mean that we must be physically represented in every single meeting."

"We recognize the importance of the direct bilateral meetings between the two leaders. We hope to proceed promptly after September 2, with meetings on an intensive basis - about every 2 weeks," Mitchell added.

On the possibility of a visit to the region by Obama in the near future, Mitchell stressed that the U.S. president “has been engaged in person from the very beginning."

"Please do not confuse personal engagement exclusively with public activities. I am certain he will make a judgment – based on reasonableness and necessity of his participation. He has many important obligations, but he places the comprehensive peace process at a very high priority," Mitchell said.

Recently, American officials have tried to avoid as much as possible mentioning Israeli settlements in the West Bank, as a 10-month moratorium on settlement construction, declared by Netanyahu last November, is about to expire on September 26. The Palestinians have announced unequivocally that if Israel resumes construction in the settlements, the negotiations would immediately break down.

“Our position on settlements is well known and it remains unchanged," Mitchell told reporters. "We always said parties should provide an environment that is conducive to negotiations. Our discussions continue with all sides on this issue."

Mitchell added that the United States was still trying to engage Syria – and that although he does not expect Islamist Palestinian faction Hamas "to play a role in this immediate process, we welcome the full participation of Hamas and all relevant parties once they comply with basic principles of democracy."

Asked about the previous peacemaking failures, Mitchell said that the Obama administration deliberately avoided labeling the current talks as a “continuation of process A or B”, but, having learned a lesson, tried “to improve what worked and avoid what didn’t work."

Obama will host a dinner for the visiting leaders on Wednesday, seeking to boost momentum for Thursday's meeting, which will mark their first direct peace talks in 20 months and the start of what Obama hopes will lead to a peace deal within a year, despite deep skepticism.

U.S. State Department spokesman P. J. Crowley said Tuesday that "we will be clarifying today where the parties stand in advance of the meetings that they'll have."

"We want to see not just a successful relaunch tomorrow but an understanding that, going forward, the leaders will meet on a regular basis," Crowley told reporters at a press conference in Washington.

Crowley said Washington expected "substantive discussions of the core issues at the heart of the process."

Political analysts are cautious about the prospects for the U.S.-backed talks, which represent Obama's riskiest foray into Israeli-Palestinian peacemaking - a goal that has eluded generations of U.S. presidents.

Obama has invited Egyptian President Hosni Mubarak and Jordan's King Abdullah to take part in Wednesday's White House events, expanding the dialogue to two influential Arab neighbors that already have peace deals with Israel.