Riad Hijab, chief coordinator of the main Western-backed Syrian opposition, attends a panel discussion at the Munich Security Conference in Munich.

A top Syrian opposition figure criticized Russia on Sunday for continuing with its bombing in Syria, insisting that people in the country need to see action rather than words.

The head of the Saudi-backed Syrian opposition’s High Negotiations Committee, former Prime Minister Riad Hijab, also stopped short of declaring a clear commitment to implement a planned temporary truce.

“You ask me if I accept a ceasefire or a cessation of hostilities. I ask you: Why is the onus on the opposition and whether it has preconditions for negotiations?” Hijab said. “I would like to see a single day of a cessation of hostilities in order to give a chance for real political movement.”

Diplomats from a group of countries that have interests in Syria’s five-year civil war, including the U.S., Russia, Turkey, Saudi Arabia and Iran, agreed on Friday to seek a temporary “cessation of hostilities” within a week. They also agreed to “accelerate and expand” deliveries of humanitarian aid to besieged Syrian communities beginning this week.

‘We need action, not words’

It remains unclear whether those commitments can be made to stick on the ground and whether deep differences regarding the truce and which groups would be eligible for it — between the U.S. and Russia among others — can be overcome.

The truce deal in Munich comes as Syrian government forces, aided by a Russian bombing campaign, are trying to encircle rebels in Aleppo, the country’s largest city, and cut off their supply route to Turkey.

Hijab questioned whether the continued fighting by Russia was “a seriously acceptable position to the international community.”

“We have gotten used to conferences and words put into hope, but what we need is action — and the action that I see is that Russia is killing Syrian civilians,” Hijab told the Munich Security Conference, an annual gathering of foreign and security policy leaders.

Speaking before Hijab, senior Republican Sen. John McCain sharply criticized the temporary truce deal, arguing that Russia is engaging in “diplomacy in the service of military aggression.”

“Let’s be clear about what this agreement does: it permits the assault on Aleppo to continue for another week. It requires opposition groups to stop fighting, but it allows Russia to continue bombing terrorists — which it insists is everyone, even civilians,” said McCain, who chairs the Senate Armed Services Committee.

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