The US president has called on Israeli and Palestinian leaders "not to let the chance for peace slip away" as he opened a US-sponsored summit to re-launch direct talks.
Barack Obama promised to put the "full weight" of the United States behind the effort "to forge peace" in direct talks between the two sides that begin at the state department on Thursday.
Peace vs. interests
Abbas and Netanyahu shook hands and pledged to "work diligently toward peace", but they also made plain that their own national interests must be satisfied.
Abbas urged Israel to freeze settlement construction in areas the Palestinians want as part of their new state, and to end its blockade of Gaza.
Netanyahu, in return, called Abbas "my partner in peace" and pledged to seek an end to the conflict "once and for all".
But he also stressed the central importance of security assurances for Israel as part of any land-for-peace agreement with the Palestinians.
Abbas' call for settlement freeze was also echoed by Hosni Mubarak, the Egyptian president.
Mubarak urged Netanyahu to make good on his vow to forge peace with the Palestinians and reiterated a plea for Israel to halt settlement activity.
"I urge Israel to reach out to the Arab hand extended for peace," Mubarak said.
"Israel should totally halt settlement activity until the peace process comes to a conclusion."
In return, King Abdullah II of Jordan warned of a "failure" and stressed the "necessity of the US commitment" to make such talks a success.
"President Obama, we need your support as a mediator, honest broker and a partner. If hopes are disappointed again, the price of failure will be too high for all," King Abdullah said.
Yousef Munayyer, the executive director of the Palestinian Center in Washington, told Al Jazeera the "risk is extremely great for Abbas" and "the road forward does not seem very promising".
"Here we have a Palestinian president who has a number of question marks surrounding the legitimacy of his leadership, who spent the entire summer telling his population that he would refuse to enter direct negotiations without a settlement freeze - yet he now enters talks without preconditions."
American officials are hopeful they can get the two sides this week at least to agree to a second round of talks, likely to be held in the second week of September.
That could be followed by another meeting among Obama, Netanyahu and Abbas on the sidelines of the UN General Assembly near the end of the month in New York.
Hurdles ahead
Al Jazeera's Nour Odeh, reporting from Nablus, said that given the current situation, there is little optimism that "peace talks" will change anything in the West Bank.
Beyond the settlements, Israel and the Palestinians face numerous hurdles in resolving other contentious issues, notably the borders of a future Palestinian state, the political status of Jerusalem security, and the fate of Palestinian refugees.
Also complicating the outlook are internal Palestinian divisions that have led to a split between Abbas' West Bank-based administration and Hamas, which controls Gaza. Hamas is not part of the negotiations and has asserted that talks will be futile.
Direct Israeli-Palestinian negotiations broke off in December 2008, in the final weeks of the George Bush administration.
PHOTO CAPTION
US President Barack Obama walks in with Egypt's President Hosni Mubarak (L), Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas (R) before making a statement on Middle East Peace talks in the East Room of the White House in Washington September 1, 2010.
Al-Jazeera