The European Union should keep all options open in dealing with Russia, including sanctions if it continues “crimes” in the besieged Syrian city of Aleppo, EU President Donald Tusk said Thursday.

“The EU should keep all options open, including sanctions if the crimes continue,” Tusk said as he arrived for an EU leaders summit dominated by a review of deeply strained relations with Moscow.

“It is really difficult if not impossible, not to refer this (discussion on Russia) to attacks on civilians and hospitals,” he added.

A draft of the summit conclusions seen by AFP earlier suggested EU leaders were weighing sanctions against backers of Syrian President Bashar al-Assad’s regime.

Moscow is Assad’s strongest ally and came to his rescue last year when rebels appeared to be gaining ground.

“The EU is considering all options, including further restrictive measures targeting individuals and entities supporting the regime, should the current atrocities continue,” the draft said.

“The European Council strongly condemns the attacks by the Syrian regime and its allies, notably Russia, on civilians in Aleppo,” it added.

Russia had upstaged the summit by announcing earlier in the week that it would halt hostilities over Aleppo on Thursday just as the 28 leaders were gathering in Brussels.

It said Thursday it would extend the truce to 11 hours from eight, and then added that it would run for three days, not one.

The EU is already embroiled in an angry stand-off with Moscow over Ukraine, complete with punishing economic sanctions on both sides.

Relations with Russia were put on the agenda of the two-day summit in Brussels months ago amid expectations of progress on Ukraine.

Since then, the deepening of the Syrian crisis has poisoned the atmosphere while talks in Berlin with Russian President Vladimir Putin on Wednesday produced no real progress.