Opening two potentially consequential days of Middle East peace talks, President Obama condemned the "senseless slaughter" of four Israelis earlier this week, reportedly by a Hamas gunman.
"The message should go out to Hamas, and everybody else who is taking credit for these heinous crimes, that this is not going to stop us from not only ensuring a secure Israel, but also securing a longer-lasting peace in which people throughout the region can take a different course," Obama said at the White House.
The president this week is hosting four foreign leaders for talks aimed at breaking an impasse in the so-called "two-state solution" for Israelis and Palestinians.
Standing with Israeli Prime Minister Benjamin Netanyahu, Obama said acts of terrorism will not derail the peace efforts.
Netanyahu, taking part in the first direct peace talks since 2008, said the killings in Hebron created "seven new orphans," but vowed to press ahead with the planned negotiations.
"The talks that we had, which were indeed open, productive, serious in the quest for peace, also centered around the need to have security arrangements that are able to roll back this kind of terror and other threats to Israel's security," Netanyahu said.
Also taking part are Palestinian President Mahmoud Abbas, President Hosni Mubarak of Egypt, and King Abdullah of Jordan. Both Egypt and Jordan previously made peace agreements with Israel.
Achieving peace in the Middle East would be a major, legacy-making achievement for Obama. The seemingly intractable conflict has stymied presidents for decades going back to the Nixon administration.
The two days of talks at the White House are not expected to conclude with a peace deal in hand. Rather, they are expected to lead to future negotiations between Netanyahu and Abbas.
For Obama, securing a deal also would provide a bulwark against Iran and that country's efforts to expand its role in the region.
Appearing later with Abbas, Obama said the process is going well.
"We are making progress," the president said.
U.S. officials are pushing for a one-year time frame to complete the process. Former Democratic Sen. George Mitchell of Maine, Obama's special envoy to the Middle East, said the leaders believe there is a "window" for achieving peace.
"It's very important to create a sense that this has a definite concluding point," Mitchell said. "We believe it can be done."
Outstanding issues include land disputes, security issues, settlement construction, borders, refugees, and more.
Joining the process at the White House is former British Prime Minister Tony Blair, who has taken an active role in brokering a deal in the Middle East. Blair was to join the other leaders for a private dinner Wednesday.
Secretary of State Hillary Clinton also is taking a leadership role, and is scheduled to meet with the leaders -- except Obama -- on Thursday.