WASHINGTON — Amid a growing consensus that ending Syria’s civil war is a critical component of the international effort to combat the so-called Islamic State (IS), US President Barack Obama said there has been modest progress at international talks in Vienna to chart a diplomatic way toward ending Syria’s civil war. But he warned that the diplomatic path ahead — comprised of parallel efforts to advance a Syrian political track while working toward a cease-fire — will be extremely difficult, despite newfound international resolve and urgency following the terrorist attacks in Paris that are believed to have been directed by IS militants in Syria.

“We’ve begun to see some modest progress on the diplomatic front,” Obama told a press conference at the G-20 summit in Antalya, Turkey, on Nov. 16.

Led by the United States and Russia, diplomats from 17 countries as well as the European Union and United Nations who met in Vienna Nov. 14 issued a plan for holding negotiations between the Syrian opposition and regime starting by Jan. 1, followed by writing a new constitution in six months and holding new elections within 18 months. The political track is supposed to be accompanied by a cease-fire that would exclude the stepped-up international fight against IS.

Noting the success of getting all of the key international stakeholders, notably including Iran and Saudi Arabia, into direct, international talks on Syria for the first time at the meetings in Vienna on Oct. 30 and Nov. 14, Obama warned, however, that continued differences including over President Bashar al-Assad’s future could shatter fragile international consensus on the path ahead.