Syrian troops pushed ahead with a new assault on the northern region of Idlib Saturday, shelling one of the centers of the uprising against President Bashar Assad's rule and sending families fleeing for safety as armed rebels tried to fend off the attack. Thick black smoke billowed into the sky. The military operation has raised fears that the regime is planning a new all-out offensive in Idlib like the bloody siege last month that captured a restive part of the city of Homs, further south. While the fighting raged, UN envoy Kofi Annan met with Assad in Damascus during a high-profile international mission trying to bring a halt to fighting and arrange talks between the two sides to end the country's yearlong conflict. Al-Assad told UN-Arab League envoy Annan Saturday that no political solution was possible in Syria while dissident groups were destabilizing the country. There was no immediate comment from Annan after his meeting with Assad, aimed at halting bloodshed that has cost thousands of lives since a popular uprising erupted a year ago. Annan also planned to meet Syrian dissidents before leaving Damascus Sunday. He has called for a political solution, but the opposition says the time for dialogue is long gone. “We support any initiative that aims to stop the killings, but we reject it if it is going to give Bashar more time to break the revolution and keep him in power,” Melham Al-Droubi, a member of the Muslim Brotherhood and of the exiled Syrian National Council, told Reuters by telephone. “We hope that Annan convinces Bashar to stop the killings, step down and call for a parliamentary election,” he said, expressing scepticism that Assad would respond positively. China has offered $2 million of humanitarian aid to Syria, state media reported, after the United Nations humanitarian chief said the conflict-riven state had agreed to an aid assessment. The aid was being offered to improve the humanitarian conditions in some regions of Syria, foreign ministry spokesman Qin Gang said Friday, according to the official Xinhua news agency. Qin said that China supported the United Nations in playing the lead role in coordinating aid efforts in Syria, Xinhua reported. No UN aid agencies are allowed into Syria, and information is scarce on the details of the civilians' needs. But UN humanitarian aid chief Valerie Amos said earlier Friday that Syria had agreed to allow a preliminary assessment of the relief needs in areas hit hard by the year-long conflict that has claimed nearly 8,500 lives. Sixteen rebels and four regular army troops were killed Saturday in clashes in Idlib province of northwest Syria, bordering Turkey, a monitoring group said. “Sixteen fighters from deserter groups were killed in an ambush near Jisr Al-Shughur town as they headed for the city of Idlib to fight regular troops,” Rami Abdel Rahman, head of the Syrian Observatory for Human Rights, said. The monitoring group also said four soldiers were killed and five captured in a separate clash in Idlib, the focus of army operations on Saturday. “Four soldiers were killed and three others wounded in an attack by a group of deserters on a military convoy near Bdama town in the Jisr Al-Shughur area. The deserters captured five other soldiers,” said the Britain-based group. International rifts have paralyzed action on Syria, with Russia and China opposing Western and Arab calls for Assad, who inherited power from his father nearly 12 years ago, to quit. The UN estimates that Syrian security forces have killed well over 7,500 people. US Secretary of State Hillary Clinton will meet Lavrov in New York on Monday on the sidelines of a special UN Security Council ministerial meeting on Arab revolts, with Syria likely to be a central topic.