AMMAN, Jordan – President 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.

Obama said he remains confident that embattled Syrian leader Bashar Assad’s government will ultimately collapse. But he warned that when that happens, 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.

More than 70,000 people have died during the two-year conflict in Syria — 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.