President Obama and King Abdullah II of Jordan warned Friday of the mounting danger Syria’s widening civil war poses to this neighboring kingdom but offered only fresh demands that the Assad government step down immediately.

Appearing for the first time in an Arab nation since his 2009 address in Cairo, Obama pledged an additional $200 million in aid to Jordan this year to help address the growing needs of almost half a million Syrian refugees, equal to roughly 10 percent of the kingdom’s population.

But Obama, speaking inside a cavernous dark-wood hall alongside the king, also raised the question he said preoccupies his administration regarding Syria. His concern is how the fighting, which has killed an estimated 70,000 people, will shape the religious and cultural makeup of a long-repressed nation.

He warned that Syria could become a beachhead for Islamist extremism, adding “that is why the United States has a stake” in the war’s outcome. Abdullah, too, warned that the increasing sectarian cast to the war threatens to pull the country apart.

Asked by a Jordanian journalist why “the leading superpower” does not intervene in Syria, Obama suggested that the unpredictable nature of the civil conflict has left him no policy option that would guarantee more good than harm, either through a direct military strike or by arming Syrian rebels.

“The sight of children and women being slaughtered that we’ve seen so much I think has to compel all of us to say, what more can we do?” Obama said. “And that’s a question that I’m asking as president every single day.”

But, he added, “ultimately what the people of Syria are looking for is not replacing oppression with a new form of oppression.”

His stop in Jordan was a show of support for Abdullah, who is facing growing calls for deeper political reforms from the same kind of mostly young population that has recently upended governments across the Middle East. He called Abdullah his “good friend” and Jordan “an invaluable ally.”

But before leaving Israel, Obama honored a pair of historic figures whose lives traced the arc of the Zionist movement — Theodor Herzl, its chief theoretician who didn’t live to see the Jewish state he envisioned, and former prime minister Yitzhak Rabin, who died trying to secure the Jewish state through a fateful peace effort with the Palestinians.

Obama made his way on a clear spring morning to Mount Herzl, where, with Netanyahu and President Shimon Peres by his side, he stepped toward the granite tomb, marked simply “Herzl” in Hebrew, on which he placed a stone in the Jewish custom.

The visit, which other foreign leaders have avoided, was meant to underscore Obama’s understanding that the modern state of Israel traces its roots to the Bible, not to the Holocaust.

Then Obama walked to Rabin’s grave, where he laid a stone that administration officials said was taken from the grounds of the Martin Luther King Jr. Memorial in Washington.

Rabin fought for Israel’s independence in 1948, and as a prime minister forged the 1993 Oslo Accords with then-Palestine Liberation Organization Chairman Yasser Arafat. The two, along with Peres, shared the Nobel Peace Prize in 1994.

The following year a Jewish extremist assassinated Rabin, and his grave has been a common stop for U.S. presidents since. Obama declined to visit Arafat’s tomb during a visit Thursday to Ramallah, another customary stop for many visiting dignitaries.

“A remarkable man,” Obama said as he shook hands with Dalia Rabin-Pelossof, Rabin’s daughter, one of several family members who joined the president at the gravesite.

After visiting the Holocaust memorial Yad Vashem, Obama set off to visit the Church of the Nativity in Bethlehem, built on the purported birthplace of Jesus.

A sandstorm grounded Obama’s planned short helicopter ride to Bethlehem, forcing him to drive into the occupied West Bank along a route that took him past the cement barrier Israel built to separate Israelis and Palestinians a few years ago.

Scattered street crowds were on hand as Obama’s motorcade entered Palestinian territory. One group of storekeepers waved and blew kisses at the motorcade.

But there were also a couple of large protest signs. “No return, no peace,” one said, apparently referring to the issue of Palestinian refugees. “Gringo, return to your country,” said another.

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