US President George W Bush has renewed his pledge to give the Israeli and Palestinian leaders his full support in reaching a peace deal in 2008.
Mr Bush wants a Middle East peace deal by the end of 2008
Mr Bush spoke after meeting Palestinian Authority President Mahmoud Abbas and Israeli PM Ehud Olmert, as they began their first peace talks in seven years.
He said Tuesday's conference was a "hopeful beginning" for Mid-East peace.
Meanwhile former Nato commander Gen James Jones has been appointed the new US Middle East envoy.
Among his tasks will be to monitor how the Israelis and Palestinians live up to the security commitments made under the "road-map" which forms the basis for the newly-relaunched negotiations.
"Building security in the Middle East is the surest path to making peace in the Middle East," US Secretary of State Condoleezza Rice said of his appointment.
"Gen Jones is the best individual to lead our efforts in this essential endeavour."
'Side-by-side in peace'
Mr Bush met Mr Abbas and Mr Olmert separately before all three of them took part in a joint session declaring the talks formally under way.
"We will use our power to help you as you come up with the necessary decisions to lay out a Palestinian state that will live side-by-side in peace with Israel," Mr Bush said in the White House Rose Garden with Mr Olmert and Mr Abbas at his side.
The BBC's James Coomarasamy in Washington says the leaders' brief appearance, without speeches or handshakes, was intended to portray a more sober and workmanlike spirit than the Annapolis conference.
According to the agreement, the Israeli and Palestinian leaders will go on to meet every other week, and teams of negotiators led by a joint steering committee will meet for the first time on 12 December.
Mr Bush - who also hosted Tuesday's meeting in Annapolis - said the two sides were committed to reaching a comprehensive peace deal by the end of next year.
But last year's parliamentary election winner Hamas - which does not recognise Israel and has been shunned by the US and Israel as a terrorist organisation - immediately rejected Annapolis as a "failure".
They say the talks were convened to prop up Mr Abbas and undermine their long-term aspirations.
In the West Bank, protests against the talks continued for a second day.
Witnesses said Palestinian police shot into the air to disperse hundreds of mourners in Hebron, who were attending the funeral of a man killed during protests on Tuesday.
At least 24 people were reported injured, one seriously, and a number of people were arrested.
Expectations had been low as representatives of more than 40 countries and international agencies gathered in Annapolis ahead of Tuesday's conference.
But in a joint statement concluded with only minutes to spare before the conference formally opened, the two sides agreed to launch negotiations for a treaty "resolving all outstanding issues, including all core issues without exception".
Both sides have said those "core issues" will include the thorny so-called "final-status issues" - the future of Jerusalem, borders, water, refugees and settlements - which have scuppered previous attempts at a peace deal.
Ms Rice hailed the consensus reached in Annapolis.
"It's going to be hard, but you had support in that room that you had not had from Arab states in the past," she said on US television.