As the UN secretary general accused the Syrian regime of potential crimes against humanity on Thursday, the top Syrian envoy to Canada blamed terrorists for civilian deaths and said President Bashar Assad still has strong support.

Fighting between government troops and Assad's opponents has been ongoing since last March, when an Arab Spring-inspired uprising first erupted in Syria.

The Syrian military has been accused of firing on civilian demonstrators, causing more than 5,000 deaths, according to some reports.

Bashar Akbik, Syrian charge d'affaires to Canada, said those numbers have not been corroborated and added that the military is battling Taliban and al Qaeda terrorists who are hiding behind civilians. He said it's the rebels themselves who are firing upon civilians, then blaming the army for the deaths.

"Those (civilians) who are falling are unfortunately falling under the fire of extremists who are intending to shoot at them and sway the world and the public's opinion that the Syrian army is the party that is shooting at civilians. We have a very complicated situation that is happening in these towns," Akbik told CTV News Channel.

He said the rebel forces are a composite of army deserters, terrorists from al Qaeda and the Taliban, and "infiltrators" from Libya, Saudi Arabia and other countries.

"We are fighting terrorists who have no bases, who have no camps, who prefer to use buildings to shoot at the army, using civilians as human shields," he said.

Akbik said Western nations, which are united in their call for Assad to step down and halt the violence, are grasping a long-sought opportunity to try and bring down the Assad government.

Meanwhile, the Syrian people are still behind their president, he said.

"The Syrian people decide his future and I would like to assure for you here, despite all you hear, President Assad still has a very strong popularity in Syria and the people are backing him more and more because they are knowing now what is the meaning to live securely and to live in peace in a country," Akbik said.

When asked why the demonstrations and clashes have carried on for nearly a year, Akbik was unable to give a clear answer. He said the government has given in to demands for greater democracy, less corruption, and even rewrote the country's constitution to reflect those changes.

On Wednesday, Assad ordered a Feb. 26 referendum on the new constitution that would create a multiparty system in Syria, which has been ruled by the same family dynasty for 40 years.

Assad's regime is touting the new constitution as the centerpiece of reforms aimed at calming Syria's chaos.

Meanwhile the rhetoric was ratcheted up Thursday in Vienna, when UN Secretary General Ban Ki-moon accused Assad's regime of potential crimes against humanity.

Activists reported renewed violence in Daraa, the city where the uprising first began 11 months ago.

Ban demanded the regime halt its use of deadly force against civilians caught between the military and armed rebels.

"We see neighbourhoods shelled indiscriminately, hospitals used as torture centres, children as young as 10 years old chained and abused," he told reporters in Vienna. "We see almost a certain crime against humanity."

The violence in Daraa includes random arrests and shootings, according to activists, and appeared to be part of a new push to eliminate hotspots in the uprising.

The UN General Assembly was to vote Thursday on an Arab-backed resolution strongly condemning human rights violations by the regime, and backing an Arab League plan to end the conflict.

Unlike in the Security Council, there are no vetoes in General Assembly votes. While the resolutions are non-binding, they are seen as a reflection of world view on various issues.

Assembly spokesperson Nihal Saad said the vote is to take place Thursday afternoon. The resolution already has 60 co-sponsors and is almost certain to be approved.

So far, Assad has paid little heed to international opinion on the conflict in his country, which has largely turned against him. China and Russia have maintained their support for the regime and refused to support any resolutions calling for Assad to step down.

Earlier this month, Moscow and Beijing vetoed a Western and Arab-backed resolution at the UN Security Council aimed at pressuring Assad to step down.

On Wednesday, the U.S. dismissed Assad's planned referendum as too little to late.

Assad "knows what he needs to do if he really cares about his people," U.S. State Department spokeswoman Victoria Nuland told reporters in Washington on Wednesday.

"The violence just needs to come to an end, and he needs to get out of the way so we can have a democratic transition."

In Vienna, the speaker of the European Parliament said Assad had lost all credibility and the notion of presenting a new constitution in the midst of what is approaching a civil war, is "inconceivable."

"The European Parliament wants to see humanitarian corridors to be put into place and shelters provided for the growing numbers of displaced people," Martin Schulz said. "The parliament urges the EU ... to help strengthening the unity of the Syrian forces which oppose the regime inside and outside the country."

Moscow has presented Assad's reform plan as an alternative way to resolve Syria's bloodshed.