In remarks made as he met Palestinian President Mahmoud Abbas, Obama called on Israel to curb settlement activity and on the Palestinians to prevent any actions that could incite confrontation.

Abbas visited the White House amid an international backlash against Israel after its forces boarded a Turkish aid ship bound for the Hamas-controlled Gaza Strip on May 31. Nine pro-Palestinian activists were killed.

Abbas, speaking after Obama, called on Israel to lift its “siege” on the Palestinian people.

Obama called the situation in Gaza unsustainable and said it was important to get all the facts out about the flotilla incident.

Obama said he would make a statement later in the day about the U.N. Security Council’s vote to approve new sanctions against Iran over its nuclear program.

Israeli Prime Minister Benjamin Netanyahu on Sunday rebuffed U.S. calls for a full settlement freeze in the occupied West Bank and vowed not to accept limits on building of Jewish enclaves within Jerusalem.

Netanyahu’s defiant stance set the stage for a possible showdown with President Barack Obama, who, in talks with the new Israeli prime minister in Washington last week, pressed for a halt to all settlement activity, including natural growth, as called for under a long-stalled peace “road map.”

“The demand for a total stop to building is not something that can be justified and I don’t think that anyone here at this table accepts it,” Netanyahu told his cabinet, referring to Jewish settlements in the West Bank, according to an official.

Netanyahu said Israel had no plans to set up any new West Bank settlements. But he told Obama, according to the official, that his government “does not accept limitations on building” within what Israel defines as its capital, the Jerusalem municipality, an area that includes Arab East Jerusalem and parts of the West Bank captured in a 1967 Middle East war.