BEIRUT — Heavy fighting broke out between rebels and President Bashar Al-Assad's forces in parts of Damascus Wednesday, as twin car bombs detonated in the central province of Homs, killing at least 12 people, activists said. The clashes in Damascus were the worst violence to hit the capital in weeks. Fighting was focused in the city's western districts, and residents in the heart of Damascus said the heavy thud of shelling was louder than in recent months when government forces tried to dislodge rebels from the capital's suburbs. Damascus has not seen the same degree of fighting as Syria's other urban centers like Aleppo and Homs, where whole neighborhoods have been destroyed. While the government has lost control of parts of those cities, it has kept a tight grip on the capital despite the rebels' attempts to storm the city center from enclaves on its outskirts. Rami Abdul-Rahman, director of the Britain-based Syrian Observatory for Human Rights, said Wednesday's shelling of Jobar and Qaboun is part of a wider government offensive against towns and villages near the capital that have been opposition strongholds since the beginning of the anti-Assad uprising in March 2011. A government official said army troops are chasing rebels in the suburbs of Harasta, Sbeineh, and Jober. Fighting also erupted in the central province of Homs, where blasts targeting a military complex killed at least 12 people and injured dozens of others, activists said. There were conflicting reports about the nature of the explosion in the city of Palmyra. The observatory said two car bombs blew up near a compound that houses a military intelligence branch and a state security agency there, killing 12 members of Syrian security forces and injuring 20 people, including eight civilians. Meanwhile, a proposal by a Syrian opposition leader for peace talks with the regime has suffered sharp setbacks, with Damascus ignoring it and a key opposing faction flatly rejecting the initiative. The peace offering by Ahmed Moaz Al-Khatib, leader of the opposition National Coalition, has been welcomed by Washington and the Arab League and was expected to receive further support Wednesday from leaders of Islamic nations meeting in Cairo. Assad himself has yet to comment on the offer by Khatib, who says "the ball is now in the regime's court", but the pro-regime Al-Watan newspaper said the offer came two years too late. The Syrian National Council, the main component of the Coalition, rejected the possibility of any talks, saying it was committed to ousting Assad's regime, rejecting dialogue with it, and protecting the revolution. — Agencies