LONDON (Reuters) - A member of Saudi Arabia’s royal family warned U.S. President Barack Obama Friday the Middle East peace process and U.S.-Saudi ties were at risk unless Washington changed tack on the Israeli-Palestinian conflict. Israel had come close to “killing the prospect of peace” with its offensive in Gaza, Prince Turki al-Faisal wrote in an article published on the Financial Times’s website.

“Unless the new U.S. administration takes forceful steps to prevent any further suffering and slaughter of Palestinians, the peace process, the U.S.-Saudi relationship and the stability of the region are at risk,” said Turki, a former Saudi intelligence chief and former ambassador to the United States and Britain.

About 1,300 Palestinians, many of them civilians, were killed and 5,000 wounded during the 22-day offensive, which ended with a ceasefire Sunday.

Israel said the campaign was designed to root out Hamas militants who fired rockets into the Jewish state. Ten Israeli soldiers and three civilians, hit by cross-border rocket fire, were killed.

Obama, sworn in as president Tuesday, named former Senator George Mitchell Thursday as an envoy with the brief to try and jump-start moribund Arab-Israeli peace talks.

Former U.S. President George W. Bush’s administration had left a “sickening legacy” in the Middle East, Turki wrote, singling out the Iraq war.

The Bush administration had also contributed to the “slaughter of innocents” in Gaza, said Turki, who currently holds no official government position in the world’s top crude oil exporter.

“If the U.S. wants to continue playing a leadership role in the Middle East and keep its strategic alliances intact -- especially its ‘special relationship’ with Saudi Arabia -- it will have to drastically revise its policies vis-a-vis Israel and Palestine,” Turki wrote. He said Iranian President Mahmoud Ahmadinejad had written to Saudi King Abdullah last week urging Saudi Arabia to lead a “jihad,” or holy war, against Israel.

This call for jihad would, if pursued, create “unprecedented chaos and bloodshed” in the region, said Turki.

“So far, the kingdom has resisted these calls, but every day this restraint becomes more difficult to maintain,” he said.

Turki urged Obama to condemn what he called “Israel’s atrocities” against the Palestinians.

Human rights group Amnesty International accused Israel of war crimes Monday over its alleged use of white phosphorus munitions in densely populated areas of Gaza. Israel has said all weapons used in Gaza complied with international law.

Turki said Obama should condemn Israeli settlement building in the West Bank and the blockade of Gaza and should call for an immediate withdrawal of Israeli forces from the disputed Shebaa Farms area claimed by Lebanon.

He urged Obama to strongly promote a 2002 Saudi peace initiative, which calls for full recognition of Israel if it gives up lands occupied in a 1967 war and accepts a solution for Palestinian refugees.