Syrian state TV, however, played down the scale of the violence, saying government troops were hunting down "terrorists" and killing large numbers of them. The government refers to those trying to overthrow Assad's regime as "terrorists."
In the capital of Damascus, the Observatory also reported attacks by government forces in the neighborhoods of Mazzeh and Barzeh that had once been held by rebels. It said that troops used helicopters gunships in the attack, causing heavy casualties.
Maj. Gen. Nabil Zughaib, described as a missile expert, was also shot dead along with his wife and a son in the Damascus neighborhood of Bab Touma, according to the Observatory.
Syrian state TV denied government forces were using helicopters in Damascus, and said the capital was calm and troops were just mopping up the remnants of the "terrorists" in cooperation with residents.
Television also showed images of calm streets in Damascus and workmen cleaning up rubble in the once-rebel held Midan neighborhood, in effort to portray a capital where everything has returned to normal.
Assad, meanwhile, appeared on state TV receiving Gen. Ali Ayyoub, the new army chief of staff, whose predecessor replaced the defense minister slain in the bombing. It was only Assad's second appearance since the attack.
Despite the regime's efforts to present an image of calm in the capital, Malaysia's government said it was shuttering its embassy in Damascus and evacuating more than 130 students and diplomats, while Italy ordered of its citizens to leave the country because of the "progressive deterioration" of the situation.
The escalating bloodshed and increasing chaos also has put Syria's neighbors on edge, particularly Israel.
Prime Minister Benjamin Netanyahu said Sunday that Israel was closely monitoring the violence in Syria for signs the regime's chemical weapons or missiles might make their way into the hands of anti-Israeli militants.
Over the weekend, Israel's defense minister, Ehud Barak, said the Jewish state was preparing for a possible attack to prevent that from happening.
For his part, King Abdullah of Saudi Arabia has announced the start of a "national campaign to collect donations to support our brothers in Syria," suggesting the oil-rich kingdom may be looking to boost its financial support for the rebels, which they are already believed to be funding.
Associated Press writers Suzan Fraser in Ankara, Turkey, and Sameer A. Yacoub in Baghdad contributed to this report.
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