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.