BEIRUT, Lebanon (AP) — Syrian troops shelled the southern city of Dara’a early on Saturday, killing at least 17 people, activists said. And in the capital, Damascus, residents spoke about a night of shooting and explosions in the worst violence the city has seen since the uprising against President Bashar al-Assad’s government began 15 months ago.

The nearly 12 hours of fighting in Damascus suggested a new boldness among armed rebels, who previously kept a low profile in the capital. It also showed a willingness by the government to unleash in the capital the sort of elevated force it has used to crush opponents elsewhere.
For the first time in the uprising, witnesses said, government tanks opened fire in the city’s streets, with shells slamming into residential buildings.
The latest escalations in different parts of Syria are another blow to efforts by Kofi Annan, the special envoy of the United Nations and the Arab League, to end the violence. Mr. Annan brokered a cease-fire that went into effect on April 12 but never properly took hold, having been violated nearly every day since then.
Foreign Minister Sergey V. Lavrov of Russia said on Saturday that Moscow’s concern about Syria’s conflict was growing, but that Russia would continue to oppose the outside use of force.
“The situation in Syria is becoming more alarming,” Mr. Lavrov said at a news conference in which he pushed Russia’s proposal for an international conference on the crisis. “An impression is being created that Syria is on the verge of a full-scale civil conflict.”
The Damascus violence was a significant shift, since the capital has been relatively quiet compared with other Syrian cities throughout the uprising. Damascus and the northern city of Aleppo, the country’s largest, are under the firm grip of Mr. Assad’s security forces.
“Yesterday was a turning point in the conflict,” said Maath al-Shami, an opposition activist in the capital. “There were clashes in Damascus that lasted hours. The battle is in Damascus now.”
The fighting began Friday, when troops opened fire on anti-Assad protest marches, witnesses said. Also on Friday, troops clashed with rebels from the Free Syrian Army in the Kfar Souseh district of Damascus.
The Free Syrian Army, which is made up of defectors from the Syrian military and protesters who have taken up weapons, had made an unusually public appearance on Thursday night in Kfar Souseh, overtly joining a large opposition rally. The bolder moves were a strong sign the group is pushing to take its fight to the government’s base of power.
The Syrian Observatory for Human Rights, an opposition group based in Britain that maintains a network of contacts in Syria, said 17 people had been killed in the shelling to the south, in Dara’a, while the Local Coordination Committees, an activist group, said 19 civilians had lost their lives. Both groups said dozens of people had also been wounded in the shelling early Saturday.
In Turkey, Syria’s main opposition council was scheduled later Saturday to elect a new leader, nearly three weeks after the resignation of its Paris-based president who offered to step down over mounting criticism of his leadership.
The group, the Syrian National Council, has been plagued by infighting and divisions since its inception in September, complicating Western efforts to help the opposition.