A Syrian woman holds a bouquet of flowers and rebel flag during a demonstration in the Bustan Al-Qasr neighborhood of Aleppo, Syria. The Britain-based Syrian Observatory for Human Rights said Friday that nearly 30,000 Syrians have been killed during the 18-month uprising against the Assad regime. — AP BEIRUT — Syrian activists say rebels and government troops have fought a fierce battle near the border with Jordan that last several hours. The activists say the fighting in and around the Syrian border town of Nasib continued until dawn Saturday. The Britain-based Syrian Observatory for Human Rights says there were casualties on both sides without giving figures. Mohammed Abu Houran, an activist in the area, says the rebels first attacked an air defense base near Nasib and as they were withdrawing they clashed with Syrian border guards. Nasib is in the southern province of Daraa, where the uprising against President Bashar Al-Assad's regime began in March last year. Rebel fighters shot down a fighter jet as it flew over the northern Syrian town of Atarib in Idlib province, a witness said. The witness, an independent journalist who asked to remain anonymous, said rebel fighters were attacking a military base near the town when the jet flew over and rebels shot it down with anti-aircraft guns. Vastly outgunned, rebels say they need surface-to-air missiles to take down planes and helicopters used by the Syrian military to bombard opposition strongholds. Fighters use outdated anti-aircraft machine guns that are welded to pickup trucks but they are inaccurate and useless if the military aircraft fly above a certain altitude. Meanwhile, government forces shelled rebel-held areas of Syria's second city Aleppo Saturday, monitors said, as the opposition warned the 18-month conflict had hit a point of “extreme gravity.” Loud explosions from shelling were heard across the northern city. The Syrian Observatory for Human Rights, which collates information from a network of activists on the ground, said artillery gunners targeted the districts of Katergi, Shaar, Sakhur, Hanano, Arkub and Marjeh. Across Aleppo province, Al-Bab and several other towns were rocked by shelling and clashes between government troops and rebel fighters, it said. The Britain-based monitoring group said security forces carried out a wave of arrests and raids in Hara, in the southern province of Daraa, where fighting broke out in Dael, another village. According to the Syrian Revolution General Commission, an activist group, regime forces torched and looted homes in the Daraa village of Heit. On Friday, when the Observatory said a total of 142 people, mostly civilians, were killed in violence across Syria, troops backed by helicopter gunships clashed with rebels near the Hanano army barracks in Aleppo. Elsewhere in the province, fighting broke out between troops and rebels near Meng military airport, the Observatory said. Germany's Manfred Lange, Chief of Staff of Supreme Headquarters Allied Powers Europe, said the “political process has to be pushed forward, sanctions need to take effect. At the moment, this situation cannot be solved by the military in a responsible way.” Also Friday, UN Secretary General Ban Ki-moon held talks with his Arab League counterpart Nabil Al-Arabi ahead of the UN General Assembly next week when Syria is expected to dominate speeches by world leaders. “They discussed first and foremost the situation in Syria, with its political impasse, widespread human rights abuses, and growing humanitarian crisis,” UN spokesman Martin Nesirky said of the talks. France is still discussing with allies whether to try to set up a no-fly zone in Syria to help rebels under assault from regime forces, a top French official said. “We are working – but not only us, a lot of countries are working – on the issue of a no-fly zone, but for the moment it is clear that it's very difficult to set up for several reasons,” said the official, who asked not to be named, during a visit to Washington. US Vice President Joe Biden, meanwhile, pressed Iraqi Prime Minister Nuri Al-Maliki in a telephone call to bar the passage of weapons shipments to Syria through Iraqi airspace, the White House said. — Agencies