The White House will step up efforts to revive the near-moribund Middle East peace process this week, with senior Obama administration officials deployed to seek progress between Israel, Syria and the Palestinians.

George Mitchell, the president's special envoy, flew to Tel Aviv today after "candid and positive" talks in Damascus with President Bashar al-Assad, who is being wooed by Obama after being shunned by the Bush administration. Mitchell went straight into a meeting with Ehud Barak, Israel's defence minister.

The US envoy said restarting talks between Israel and Syria was a "near-term goal" for Washington. "I told President Assad that President Obama is determined to facilitate a truly comprehensive Arab-Israeli peace," he told reporters.

Indirect negotiations between Syria and Israel, mediated by Turkey and centred on the occupied Golan Heights, were suspended during Israel's offensive against the Gaza Strip in December. Turkey said earlier this month it was ready to resume mediation efforts.

But there has been no public sign from Syria that Assad has agreed to influence Hamas, the Palestinian Islamist movement that controls Gaza, and the bitter opponent of the West Bank-based Palestinian Authority. Hamas, listed as a terrorist organisation by the US and Britain, is based in Damascus.

The US is sending an ambassador back to Syria after withdrawing the previous incumbent in 2005 in protest at the Beirut assassination of Rafiq al-Hariri, the former Lebanese prime minister, which was widely blamed on Damascus, despite repeated denials.

Syria's foreign minister, Walid al-Muallem, said in London on Friday that Damascus - Tehran's only Arab ally - could help find a way out of the impasse over Iran's nuclear ambitions, complicated by domestic turmoil since last month's disputed presidential elections.

Underlining intensifying US diplomacy in the region, the defence secretary, Robert Gates, is also due in Israel tomorrow for talks with Barak and Binyamin Netanyahu, the prime minister, on missile defence, Iran and bilateral security issues.

General Jim Jones, Obama's national security adviser, and Dennis Ross, a senior Middle East and Iran expert, are also due to in Israel.

The flurry of high-level activity follows Obama's long-heralded speech to the Arab and Muslim worlds in Cairo in June, when the president made clear his strategic commitment to working to achieve Middle East peace. These latest moves are intended to achieve concrete results.

Mitchell and Barak have been trying to agree a delicate compromise on freezing Israeli settlement activity in the West Bank - a hot potato in Israeli domestic politics but vital if Arab countries are to take any steps, at the urging of the US, to "normalise" relations with Israel.

Netanyahu has pledged not to build new outposts or expropriate territory in the West Bank. But he insists construction must continue to accommodate "natural" Jewish population growth. The precise definition of a moratorium has yet to be agreed, though Israeli officials speak of exempting 2,500 housing units that are still being built. Palestinians and Arabs say a total freeze is the minimum required and accuse Netanyahu of bad faith.

Mitchell is also due to see Mahmoud Abbas, the Palestinian president, at his Ramallah headquarters.

In London, meanwhile, the all-party Commons foreign affairs committee urged the British government to talk to moderates within Hamas. Russia is the only member of the Quartet of Middle East peace brokers - which also comprises the US, UN and EU - which talks to Hamas. "We conclude that there continue to be few signs that the current policy of non-engagement is achieving the Quartet's stated objectives," the committee said. "The credible peace process for which the Quartet hopes, as part of its strategy for undercutting Hamas, is likely to be difficult to achieve without greater co-operation from Hamas itself."

Israel remains implacably opposed to any dealings with Hamas, but pressure has been growing elsewhere for change. In March, Britain changed tack by announcing that it would end its boycott of the political wing of Lebanon's Iranian-backed Hezbollah - which is represented in the Lebanese parliament - but it remains opposed to talking to the Palestinian group.