(CNN) -- The stench of the burnt bodies was so potent, Abu Jafar said, he could smell it from 2 kilometers (1.2 miles) away. 

"It smells awful because the regime appears to have burnt so many bodies recently," the opposition activist said Sunday from the beleaguered city of Homs. 

"Some cars arrived this morning and carried away dead bodies. We are not sure where." 

Read more: Deadly day in Syria as diplomats talk 

Jafar's account comes a day after what may be the deadliest day yet in Syria's 21-month civil war, according to opposition figures. 

Lakhdar Brahimi, the joint U.N.-Arab League envoy, gave a dire warning Sunday on the rapidly deteriorating situation in Syria. 

"If nearly 50,000 people have been killed in about two years, do not expect just 25,000 people to die next year -- maybe 100,000 will die," he told reporters in Cairo. 

"The pace is increasing," he said. 

"A solution is still possible, but it is only getting more complicated every day," Brahimi added. "Had we dealt more carefully with this conflict in 2011, it would have been much easier to resolve it. There is no question that it is much harder today." 

Read more: 'Til death do us part: Marriage destroyed by war 

Brahimi met Sunday with Nabil Elaraby, secretary-general of the Arab League. 

On Saturday, Brahimi met with Russian Foreign Minister Sergey Lavrov. Russia and China have used their veto power in the U.N. Security Council to block some of the toughest resolutions proposed against the Syrian regime. 
who was speaking to reporters?
Lakhdar Brahimi