AMMAN, Jordan (AP) - President Barack Obama warned Friday that an "enclave for extremism" could fill a leadership void in war-torn Syria, a chilling scenario for an already tumultuous region, especially for Jordan, Syria's neighbor and a nation at the crossroads of the struggle for stability in the Middle East.
In a significant step toward easing regional tensions, Obama also brokered a phone call between leaders from Israel and Turkey that resulted in an extraordinary apology from Israeli Prime Minister Benjamin Netanyahu for a deadly 2010 raid on a Gaza-bound Turkish flotilla. The call marked a diplomatic victory for the president and a crucial realignment in the region, given Israel's and Turkey's shared interests, in particular the fear that Syria's civil war could spill over their respective borders.
Obama said he remains confident that embattled Syrian leader Bashar Assad's government will ultimately collapse. But he warned that when that happens, Syria would not be "put back together perfectly," and he said he fears the nation could become a hotbed for extremists.
"I am very concerned about Syria becoming an enclave for extremism, because extremists thrive in chaos," Obama said during a joint news conference with Jordan's King Abdullah II. "They thrive in failed states, they thrive in power vacuums."
More than 70,000 people have been killed during the two-year conflict in Syria, making it by far the deadliest of the Arab Spring uprisings that have roiled the region since 2011. Longtime autocrats in Egypt, Tunisia, Yemen and Libya have been ousted, ushering in new governments that are sometimes at odds with the Obama administration and its Mideast allies.
Obama's 24-hour stop in Jordan marked his first visit to an Arab nation since the 2011 Mideast protests began. Jordan's monarchy has clung to power in part by enacting political reforms, including parliamentary elections and significant revisions to the country's 60-year-old constitution. Still, tensions continue to simmer, with the restive population questioning the speed and seriousness of the changes.
Protecting Abdullah is paramount to U.S. interests. The 51-year-old king is perhaps Obama's strongest Arab ally and a key player in efforts to jumpstart peace talks between Palestinians and Israel. Jordan has a peace treaty with Israel, and that agreement has become even more significant given the rise of Islamist leaders in Egypt, which was the first Arab country to ink a treaty with the Jewish state, in the 1970s.
Egypt's new leaders have so far pledged to uphold the treaty, though there are strong concerns in Israel and the U.S. about whether that will hold.
By virtue of geography, Jordan's future is particularly vulnerable to the turmoil in the Middle East. It shares borders with Iraq, Israel and the West Bank, in addition to Syria. More than 460,000 Syrians have flowed across the Jordanian border seeking refuge since the civil war began, seeking an escape from the violence.
The flood of refugees has overwhelmed the country of 6 million people, straining Jordan's resources, including health care and education, and pushing the budget deficit to a record high $3 billion last year. Abdullah also fears the half-million refugees could create a regional base for extremists and terrorists, saying recently that such elements were already "establishing firm footholds in some areas."
Obama announced that his administration planned to work with Congress to allocate $200 million to Jordan to help ease the financial burden.
Despite the influx, Abdullah firmly declared Jordan would not close its borders to the refugees, many women and children.
"This is something that we just can't do," he said. "It's not the Jordanian way. We have historically opened our arms to many of our neighbors through many decades of Jordan's history."
Obama had come to Jordan from Israel, where he spent three days coaxing Netanyahu to apologize to Turkish Prime Minister Recep Tayyip Erdogan for Israel's role in the deaths of nine Turkish activists during a naval raid on a Gaza-bound international flotilla. The 20-minute phone call took place just before Obama departed, in a trailer on the airport tarmac near a waiting Air Force One, and resulted in the restoration of normal diplomatic relations between the two countries.
"The timing was good for that conversation to take place," Obama said, adding that the phone call was the first step in rebuilding trust between Israel and Turkey.
The president opened the last full day of his Mideast trip with a series of stops around Jerusalem and Bethlehem, all steeped in political and religious symbolism.
Accompanied by Netanyahu and Israeli President Shimon Peres, Obama laid wreaths at the graves of Theodor Herzl, the founder of modern Zionism who died in 1904 before realizing his dream of a Jewish homeland, and former Israeli Prime Minister Yitzhak Rabin, who was assassinated in 1995.
Obama and his hosts arrived at the Herzl grave site under cloudless skies. Obama approached Herzl's resting place alone and bowed his head in silence. He turned briefly to ask Netanyahu where to place a small stone in the Jewish custom, then laid the stone atop the grave.
"It is humbling and inspiring to visit and remember the visionary who began the remarkable establishment of the State of Israel," Obama wrote in a guestbook. "May our two countries possess the same vision and will to secure peace and prosperity for future generations."
At Rabin's grave a short walk away, Obama was greeted by members of the late leader's family. He initially placed a stone on Rabin's wife's side of the grave, then returned to place one atop Rabin's side. In a gesture linking the U.S. and Israel, the stone placed on Rabin's grave was from the grounds of the Martin Luther King memorial in Washington, the White House said.
Friday's stop at Herzl's grave, together with Obama's earlier viewing of the Dead Sea Scrolls, the ancient Hebrew texts, were an attempt by the president to emphasize his view that the rationale for Israel's existence rests with its historical ties to the region and with a vision that predated the Holocaust. Obama was criticized in Israel for his 2009 Cairo speech in which he gave only the example of the Holocaust as reason justifying Israel's existence.
Obama was to make a stop Saturday at Petra, Jordan's fabled ancient city, before flying back to Washington.