People wait amid rubble at a military checkpoint in the town of Beit Sahm, Syria, before going to buy food and other essentials. (AP)

— A top U.N. official warned Thursday of the consequences of allowing Syria’s war to rage unchecked for yet another year as Russia intensified the first diplomatic push in a year to end to the devastating conflict.

Expectations that the Russian effort will succeed where others have failed are low: The factions remain far apart, and the main opposition groups have so far said they will not participate in talks with the Syrian government that Moscow is planning to host at the end of the month.

U.N. special envoy Staffan de Mistura told journalists in Geneva on Thursday that he was “hoping, more than expecting” that the talks will herald at least the beginning of an end to a conflict that has killed 220,000 people, injured more than a million and forced nearly half of the Syrian population to flee their homes.

He cited last week’s attacks in Paris as one of the consequences of failing to end the conflict, which has helped fuel the virulent brand of extremism that directly inspired at least one of the French gunmen.

“This is why we cannot avoid raising a flag today of urgent concern,” he said.

Residents walk in a damaged neighborhood in Maaret al-Naaman town in the Idlib province of Syria. (Khalil Ashawi/Reuters)

He pointed to the Russian initiative as the only diplomatic effort currently underway to end the war, and the first since U.S.-backed talks in Geneva collapsed a year ago.

“We are in favor of any initiative, and this one is a serious initiative, we hope,” he said.

The Russian diplomacy received a boost Wednesday when U.S. Secretary of State John F. Kerry appeared to endorse the attempt to bring the warring sides together again. “We hope that the Russian efforts could be helpful,” he said after meeting in Geneva with de Mistura.

The initiative has the modest goal of bringing together representatives of the opposition and the government for open-ended discussions about their differences. It is intended as a prelude to more formal negotiations aimed at securing a wider political settlement. The talks are tentatively scheduled for Jan. 26-29 in Moscow, though earlier this week Syria’s official news agency SANA indicated the date may change.

Syria’s main opposition groups have said they will not attend, citing the absence of guarantees that the goal of the talks will be a transition of power. Russia is one of Syria’s chief allies and a major supplier of military aid to the government, and opposition figures say they fear the effort is intended only to cement President Bashar al-Assad’s hold on power in Damascus.

That position may be revised, however, after talks to be held in Cairo next week aimed at forging a unified approach among rival opposition factions, opposition figures say. Those talks will bring together representatives of the principal opposition group, the Istanbul-based Syrian National Coalition, and the Damascus-based National Coordination Committee, which does not support the armed rebellion but seeks reforms in Syria.

“On Moscow, it’s a ‘no’ right now,” said an official with the Syrian National Coalition, who spoke on the condition of anonymity in order not to preempt the talks. “Moscow will be revisited after the talks in Cairo are concluded.”

De Mistura spelled out the mounting costs of the failure to address the war. Syria already represents the worst humanitarian disaster since World War II, he said, and continued deterioration could push a solution even further out of reach.

“Syria has gone now 40 years backwards from where it was” when the violence erupted in 2011, he said. “What we need to make sure is that this does not become like 2014, when we heard similar appeals from all of us . . . and then nothing really happened.”

Circumstances have changed in the year since the Geneva peace talks collapsed, he noted. The expansion of the Islamic State in northern Syria and the launch of the U.S.-led air war against the militant group in Syria and Iraq may have increased pressure on Assad to seek a solution, de Mistura said.

But in an interview with a Czech newspaper published Thursday, Assad indicated he is no closer to meeting the opposition’s demands than he was a year ago. He cited as his key objectives “fighting terrorism” and supporting the Syrian army in its fight against the rebellion.