Smoke rises from buildings in the northern Syrian city of Aleppo | George Ourfalian/AFP via Getty Images EU leaders shy away from new Russia sanctions Several countries had urged a ramped-up response to Moscow.

Brushing aside an aggressive push by Germany, France and Britain, EU leaders rejected a proposal to pointedly threaten new sanctions against Russia and other supporters of the Syrian government, despite widespread outrage over devastating air strikes and civilian casualties in Aleppo.

The unsuccessful bid for a threat of new sanctions highlighted deep fractures in the bloc, which continue to complicate efforts to develop a cohesive response to an increasingly aggressive Kremlin. The EU's three largest powers were eager to send a warning to Russian President Vladimir Putin over what they have called "atrocities" and "war crimes" in Syria. However, some other countries -- notably Italy -- argued that even a hint of punitive action against Russia was potentially counter-productive.

The debate over threatening additional sanctions came during dinner at the EU's autumn summit, a day after French President François Hollande and German Chancellor Angela Merkel met in Berlin with Putin and President Petro Poroshenko of Ukraine to push for implementation of the Minsk 2 peace accord.

After the talks about Ukraine, Merkel and Hollande met separately with Putin about Syria and said they spoke in blunt terms about the need for Russia to halt its bombing campaign. Russia unilaterally declared a ceasefire earlier this week and said it would help open transit routes for humanitarian aid, demonstrating once again that Russia was both in control of events on the ground in Syria and fully intent on operating on its own terms.

The dinner conversation was supposed to be about long-term policy, and had been requested by Italian Prime Minister Matteo Renzi, who has long had misgivings about the existing sanctions against Russia over Ukraine. But many EU leaders were infuriated over the suffering of civilian victims in Aleppo, and that topic became a major stumbling block in reach agreement on the summit's final written conclusions.

British Prime Minister Theresa May, who was attending her first EU summit, made a strong pitch for a tougher stance against Russia, urging her fellow leaders to ramp up the EU’s response to what she called Moscow’s “sickening atrocities” in Syria.

The U.K. leader demanded that fresh sanctions on the Putin regime be kept on the table.

But draft language that specifically referenced a threat of "further restrictive measures" was rejected. Instead, the leaders settled on more vague wording saying, "The EU is considering all available options should the current atrocities continue."

The disagreements over Russia were just one of the problems EU leaders wrestled with at the summit. Even more embarrassing was the failure on Thursday to conclude a trade agreement with Canada, despite some last-ditch concessions to regional lawmakers in Belgium who have blocked the deal. The leaders were due to take up the trade talks on Friday.

Summing up the leaders' discussion on Syria, European Council President Donald Tusk said: "They strongly condemned the attacks by the Syrian regime and its allies, notably Russia, on civilians in Aleppo. The EU is calling for an end to the atrocities and an immediate end to the cessation of hostilities."

He added, "It considers all available options if these atrocities continue."

While Renzi — backed up by EU foreign affairs chief Federica Mogherini — succeeded in blurring the language on sanctions, by all accounts the conversation he initiated on Russia focused far less on the important economic and energy ties that he had hoped to stress and instead became a wide-ranging gripe session about the Kremlin's increasing belligerence and appetite for military aggression, political meddling and propaganda attacks.

"Leaders emphasized all sorts of Russian activities," Tusk said, "from airspace violations, disinformation campaigns, cyber attacks, interference into the political processes in the EU and beyond, hybrid tools in the Balkans, to developments in the MH17 investigation."

"Given these examples," Tusk added, "It is clear that Russia's strategy is to weaken the EU. We have a sober assessment of the reality and no illusions."

And yet, the EU leaders put forward no new response.

Arriving at the summit in Brussels, a number of leaders again voiced their dismay about the situation in Syria.

Estonian Prime Minister Taavi Rõivas said the EU needed "to give a very clear message to both the Syrian regime and its allies, mainly Russia, on the fact that the ambition of turning Aleppo into a new Grozny, this is absolutely unacceptable." Grozny, the capital of Chechnya, was largely reduced to rubble during two brutal wars in which Russia succeeded in suppressing Islamic separatists.

On Wednesday, leaders of three political factions in the European Parliament sent a letter to Tusk demanding action on Syria. And in a speech to EU leaders on Thursday, Martin Schulz, the president of the European Parliament, reiterated the call.

"I come with a clear message to you from the European Parliament: Acting to stop the bloodshed in Syria should be the number one priority on your list," he said, according to prepared remarks.

Several leaders, including Merkel, expressed a desire to maintain good relations with Russia even as they demanded an end to hostilities in Syria. But leaders also said the Kremlin was making such good relations impossible.

"Increasing tensions with Russia is not our aim," Tusk said. "We are simply reacting to steps taken by Russia. Of course, the EU is always ready to engage in dialogue, but we will never compromise our values or principles."