This citizen journalism image provided by Aleppo Media Center AMC which has been authenticated based on its contents and other AP reporting, shows planes on the ground at the Kweiras military air base in Aleppo province, Syria, Sunday, May. 5, 2013. Syrian Observatory for Human Rights said rebels moved deep inside Mannagh air base, near the border with Turkey, while under fire from government warplanes. (AP Photo/Aleppo Media Center AMC)
BEIRUT (AP) — Syrian rebels shot down a military helicopter in the country's east, killing eight government troops on board as President Bashar Assad's troops battled opposition forces inside a sprawling military air base in the north for the second straight day, activists said Monday.
In the past months, rebels fighting to topple President Bashar Assad have frequently targeted military aircraft and air bases in an attempt to deprive his regime of a key weapon used to target opposition strongholds and reverse rebel gains in the 2-year-old conflict.
The fighting inside the Mannagh air base in northern Syria came a day after Israeli warplanes struck areas in and around the capital, Damascus, setting off a series of explosions as they targeted a shipment of highly accurate, Iranian-made guided missiles believed to be bound for Lebanon's Hezbollah militant group, officials and activists said.
The Britain-based Syrian Observatory for Human Rights on Monday posted a video online showing several armed men standing in front of the wreckage. One of the fighters in the footage says it's a helicopter that the rebels shot down late Sunday in the eastern province of Deir el-Zour, along Syria's border with Iraq.
As the man speaks, the camera shifts to a pickup truck piled with bodies. The fighter is then heard saying that all of Assad's troops who were aboard the helicopter were killed in the downing. He says Islamic fighters of the Abu Bakr Saddiq brigade brought down the helicopter as it was taking off from a nearby air base in the provincial capital of Deir el-Zour.
The Observatory, which relies on a network of activists on the ground, said eight troops were killed.
On Sunday, rebels occupied parts of the Mannagh military air base after weeks of fighting with government troops who have been defending the sprawling facility near the border with Turkey for months, the Observatory said.
Assad's warplanes were pounding rebel positions inside the Mannagh air base Monday as clashes between rebels and government forces raged on, the Observatory said, adding there was an unknown number of casualties on both sides.
The rebels moved deep into the air base on Sunday despite fire from government warplanes, capturing a tank unit inside the base and killing the base commander, Brig. Gen. Ali Salim Mahmoud, according to another activists group, the Aleppo Media Center.
The Israeli airstrike on Sunday, the second in three days and the third this year, signaled a sharp escalation of Israel's involvement in Syria's civil war. Syrian state media reported that Israeli missiles hit a military and scientific research center near Damascus and caused casualties. The reports did not specify the number or say if the casualties were civilians or troops.
State-run SANA news agency made no mention of the fighting inside the Mannagh air base. But the agency reported that government troops on Monday regained control of villages along the highway that links the northern city of Aleppo to its civilian airport, the country's second largest.
Syrian "armed forces restored security and stability to (six) villages" south of the city and along the airport highway, SANA said, calling it a "major strategic victory in the north."
Much of the north has been in rebel hands since the opposition fighters last summer launched an offensive in the area, capturing army bases and large swaths of land along the border with Turkey and whole neighborhoods inside Aleppo, Syria's largest city.
The rebels have for months battled regime troops over the airport complex that includes army bases and a military air field. They've captured village and towns along the strategic highway and earlier this year advanced within a few kilometers (miles) miles of the airport, cutting the main road the army has been using to ferry troops and supplies to its bases at the airport.
But last month government troops recaptured the village of Aziza on a strategic road that links Aleppo with its airport and military bases, dealing a huge setback to the rebels unable to hold on to the territory in the face of Assad's superior fire power.
The Syrian conflict started with largely peaceful protests against Assad's regime in March 2011, but eventually turned into a civil war that has killed more than 70,000 people according to the United Nations.
More than one million Syrians have fled their homes during the fighting and sought shelter in neighboring countries such as Jordan, Lebanon and Turkey. Millions of others have been displaced inside Syria.
In Geneva, former war crimes prosecutor Carla Del Ponte said a U.N. commission has indications that Syrian rebel forces used nerve agent sarin as a weapon in their fight against Assad's regime — but no evidence that government forces also used sarin as a chemical weapon.
Del Ponte is on the U.N.'s four-member independent human rights panel probing alleged war crimes and other abuses in Syria. She told Italian-language Swiss public broadcaster SRI in an interview broadcast Sunday night that the indications are based on interviews with victims, doctors and field hospitals in neighboring countries.
The panel's investigators have "strong, concrete suspicions but not yet incontrovertible proof of the use of sarin gas, from the way the victims were treated," said del Ponte.
Associated Press Writer John Heilprin contributed to this report from Geneva.
Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.