Arab league foreign ministers are calling on Syrian President Bashar al-Assad to resign rapidly and have offered his family safe passage out of Syria.
However, a BBC correspondent in neighbouring Lebanon says Mr Assad appears to have ignored the call.
Mr Assad held a meeting with his new army chief of staff and gave him instructions, reportedly including a drive to crush armed rebels.
Meanwhile, rebel fighters have told another BBC correspondent, who is undercover near the Syrian capital Damascus, the deaths of four top officials were a severe blow to the government.
The correspondent says Islamist rebels where he is are receiving weapons and money from outside.
Fighting is continuing in Syria's two main cities, with government forces recapturing the Damascus suburbs of Barzeh and Mezzeh.
There and in other quarters, activists say a number of suspected rebels or sympathisers were summarily executed, the BBC reports.
Fighting is also reported in Syria's second city, Aleppo.
Syrian state TV is playing down the scale of the violence, saying troops were merely hunting down what it calls "terrorists".
Both sides targetting children - charity
A British charity, War Child, says all parties in the Syrian conflict are targeting children, who are facing execution-style killings, serious injuries, abductions and rapes.
In what it says is the first comprehensive assessment of the effect of the crisis on children, the charity accuses both sides of enlisting children.