Fighters from Syrian al Qaeda wing close in on Shi'ite village BEIRUT (Reuters) - Members of al Qaeda's Nusra Front and other Sunni Islamists seized an area south of a Shi'ite Muslim village in north Syria on Sunday after clashes with pro-government fighters, opposition activists said. The insurgents advanced overnight on al-Zahra, north of Aleppo city, seizing territory to the south and also trying to take land to the east in an attempt to capture the village, the Britain-based Syrian Observatory for Human Rights said. Al-Zahra and the nearby village of Nubl have been under a long siege by anti-government forces in an isolated Shi'ite area. The United Nations said in March that armed groups surrounding the villages had cut electrical and water lines supplying 45,000 residents. The army has used helicopters to drop supplies to the villagers. Opposition activists said the fighters also targeted Nubl and were seeking to capture both in the advance on the villages, which are located along a highway that leads to Turkey. Control of the villages could open up a new supply line into Aleppo for the insurgents. "We targeted the town with dozens of mortar shells and dozens of hell cannon shells and Nusra's forces made progress and control buildings which are in the first line of defense of Nubl," said media activist Ahmed Hamidou who was accompanying battalions involved in the campaign. The clashes killed at least eight of the fighters advancing on al-Zahra and a number of fighters from the pro-government National Defense Force, the Observatory said. Villagers from both al-Zahra and Nubl backed up forces trying to stop the Nusra-led offensive, activists said, adding that the Syrian air force had also reacted by bombing several other villages north of Aleppo. An opposition spokesman said in January that the area had been surrounded because it had been used as a launching pad by the Syrian military to attack Aleppo. The opposition said at the time it could lift the siege if the Syrian military reciprocated elsewhere, but this had not happened. Aleppo and surrounding areas have been hit by heavy fighting in a conflict which is now in its fourth year and has killed some 200,000 people, according to the United Nations. The U.N.'s Syria mediator has said that Aleppo would be a good starting point for local ceasefire agreements and has discussed the idea with President Bashar al-Assad. Further east, Islamic State fighters shot down a Syrian war plane on Sunday close to the eastern city of Deir al-Zor, the Observatory reported, the first time the militant group had taken down an aircraft in that part of the country. Reporting by Sylvia Westall; Editing by Raissa Kasolowsky and Stephen Powell