Mr Obama spoke after hosting the first meeting between leaders from both sides since he took office.

US Middle-East envoy George Mitchell later said the US did not see any issue as a precondition for talks.

The US has been pressuring Israel to comply with Palestinian demands for all building in settlements in the occupied West Bank to end before talks restart.

Israeli Prime Minister Benjamin Netanyahu and Palestinian leader Mahmoud Abbas shook hands in front of the cameras during what was their first encounter since Mr Netanyahu came to office in March.

Mr Obama - who has defined peace between Israel and the Palestinians as a "national interest" of the US - first met each leader separately in what he described as "frank but productive" talks, before hosting the trilateral meeting.

"Permanent status negotiations must begin and begin soon," he said. "It is past time to talk about starting negotiations. It is time to move forward."

In a news conference later, Mr Mitchell said the meeting had been "cordial" and at times "blunt", but that Mr Netanyahu and Mr Abbas had "recognised the urgency of moving promptly".

He said that while no agreement had yet been reached on the issue of Israeli settlement building in the West Bank and East Jerusalem, there were no preconditions for talks to restart.

"Our objective all along has been to re-launch meaningful final status negotiations in a context that offers the prospect of success," Mr Mitchell said.

"We have substantially and significantly progressed in reducing the number of issues on which there is disagreement and we hope to complete that process in the near future."

Israel has repeatedly rejected US and Palestinian demands for a total freeze on settlement building.

Speaking after the talks, Mr Netanyahu said there had been a "general agreement that the peace process should resume as soon as possible with no preconditions".

Mr Obama said Israel had discussed important steps to "restrain" settlement activity, in what some observers noted to be a change in language from his previous calls for Israel to "halt" or "freeze" all building work.

But Mr Abbas reiterated his demand that all construction in settlements be frozen.

He said he had called on Israel to "respect the roadmap to peace" and withdraw back to what he called its internationally recognised boundaries before the 1967 war.

The roadmap is a US-backed 2003 peace initiative under which Israel agreed to stop settlement building and Palestinians to clamp down on militant activity.

Low expectations

Mr Obama had initially hoped to launch new peace negotiations at the UN General Assembly.

But prior to the meeting, the White House played down hopes, saying it had no "grand expectations".

Israeli and Palestinian participants had also said they did not expect many concrete developments.

Israeli government secretary Zvi Herzog said the talks were "a step in the right direction", but conditions were "not ripe for a formal re-launch of negotiations".

Last week, a senior Palestinian official suggested his side was taking part so as not to disappoint the US and that doing so did not mean a resumption of peace talks.

Disagreements over the settlements issue have blocked all attempts to restart peace talks since they were suspended last December.

Mr Netanyahu has previously offered a temporary construction freeze for several months, but not in East Jerusalem or in cases where homes had already been approved.

He argues that the "natural growth" of settler families must be accommodated.

Hamas, Mr Abbas's rivals who control Gaza, condemned the talks as "cover for Israeli aggression", while Israeli settlers opposed to a settlement freeze set up a protest tent in Jerusalem.