DAMASCUS, Syria -- Syrian troops and tanks drove rebels from a Damascus neighborhood Friday where some of the heaviest of this week's fighting left the streets littered with gutted cars and bodies.
Meanwhile Friday, activists reported that 310 Syrians were killed in violence the day before, making it the single deadliest day of fighting since the revolt began in March 2011.
A fourth member of President Bashar Assad's inner circle, national security chief Gen. Hisham Ikhtiyar, died Friday of wounds he suffered in a rebel bomb blast that went off Wednesday during a high-level security meeting in Damascus.
The bombing was a resounding blow to Assad, killing his defense minister and his influential brother-in-law and another security official. All were central to directing the crackdown on the uprising against his rule.
The blast, six days of sustained fighting in neighborhoods across the capital and the fall of several border posts into rebel hands have pointed to the unraveling of Assad's grip on power amid an uprising that began with peaceful protests inspired by the Arab Spring but became increasingly militarized as the opposition took up arms.
Regime troops regained control of the district of Midan in the southern part of Damascus on Friday and eagerly took journalists on a tour to prove it.
Damascus activist Khaled al-Shami said rebels carried out a tactical retreat early Friday to spare civilians further shelling after five days of intense clashes between opposition fighters and regime forces. Rebels launched new fighting in several other districts of the capital, activists said.
The fighting came as Muslims around much of the world began marking Islam's annual Ramadan fast, abstaining from food or drink from sunrise to sunset. In a sign of the increasing sectarian split in Syria, the mainly Sunni opposition said it was starting the fast on Friday, along with Saudi Arabia and most Sunni-led Arab nations. The regime, meanwhile, said it would begin Saturday, as would its ally, Shi'ite-led Iran.
Battles have turned parts of Damascus into combat zones and sent thousands of Syrian families packed in cars streaming across the border into neighboring Lebanon.
Also Friday, the United Nations Security Council voted to extend the mission of 300 unarmed observers in Syria for 30 days. The team was meant to oversee a cease-fire that was to begin in mid-April but never took hold. In recent weeks, violence has kept the observers largely confined to their hotels.
The UN vote extends the mission, which was set to expire Friday, for 30 days, though it can be extended again if Syrian troops stop using heavy weapons in populated areas and the overall level of violence drops.
On Thursday, Russia and China vetoed a resolution backed by Western nations that would have imposed new sanctions on Assad's regime.