Rebels battle Syrian forces in Damascus (AP) BEIRUT - Bullets and shrapnel shells smashed into homes in the Syrian capital overnight, as troops battled rebels in the streets, in the heaviest fighting yet in Damascus. The violence marked an increased boldness among rebels in taking their fight against the regime of President Bashar Assad to the center of his power. For nearly 12 hours of fighting that lasted into the early hours Saturday, rebels armed mainly with assault rifles fought Syrian forces. U.N. observers said rebels fired a rocket-propelled grenade at the local power plant, damaging parts of it and charring six buses, according to video the observers took of the scene. Syrian forces showed the regime's willingness to unleash elevated force in the capital: at least three tank shells slammed into residential areas in the central Damascus neighborhood of Qaboun, an activist said. Intense exchanges of assault-rifle fire marked the clash, according to residents and amateur videos. At least 42 civilians were killed in violence around the country outside Damascus on Saturday, according to the Syrian Observatory for Human Rights, a Britain-based activist group. Among them were 20, including nine women and children, who died in heavy, pre-dawn shelling in the southern city of Daraa, where the uprising against Assad began in March 2011. The group's figures could not be independently confirmed. In a Daraa mosque, a father stood over his son killed in the shelling, swaddled in a blanket. "I will become a suicide bomber!" the father shouted in grief, according to an amateur video of the scene. Later Saturday, tens of thousands of Daraa residents buried the slain from the shelling. They sang, danced and paraded the dead in coffins around a large square, giving the mass funeral the appearance of a mass wedding party, according to footage of the scene. The Damascus violence was a dramatic shift, since the capital has been relatively quiet compared with other Syrian cities throughout the uprising. Damascus, Assad's stronghold, and the northern city of Aleppo, the country's largest, are under the firm grip of security forces. To watch Elizabeth Palmer's report from Syria, and then analysis of Syrian's military capabilities by CBS NEws senior military security analyst Gen. Richard Myers, click on the video player above. The rebels' brazenness in appearing in the Damascus districts underscored deep-seated Sunni anger against the regime, with the neighborhoods' residents risking their safety - and potentially their lives - to shelter the fighters. Residents burned tires to block the advance of Syrian troops, sending plumes of smoke into the air, according to amateur video of one scene. Urban Sunni Syrians had once mostly stayed at arms' length from their mostly rural compatriots leading the 15-month uprising, fearing the instability that their leaderless, chaotic movement would bring. But it appears a series of massacres of mainly Sunni peasants over the past few weeks have tipped some of their urban brethren in favor of the uprising. One rebel supporter in Qaboun said the recent mass killings made people see rebel fighters more as protectors against Assad's forces. The regime has forced the rebels into the city. When they commit attacks, or massacres, or arrests, they come in to defend residents," he said.