DAMASCUS, Syria — A senior United Nations team tasked with investigating the alleged use of chemical weapons in Syria's civil war began a mission to Damascus Wednesday, trying to hammer out with Syrian officials the terms for their investigation.
It is the first such trip by international experts, and the talks were expected to be thorny — focusing on about a dozen incidents in which chemical arms were allegedly used. The rebels, the U.S. and others have accused the government of using the weapons of mass destruction, while Damascus and its ally Russia have blamed the rebels.
The delegation's arrival coincided with intense fighting in neighborhoods on the edge of the capital.
Activists and residents reported heavy clashes in the Jobar district, parts of which are held by rebels trying to topple President Bashar Assad. Several mortar shells fired from Jobar crashed into residential neighborhoods in Damascus.
"I was in the bedroom and my parents were in the sitting room when a mortar shell crashed into our apartment," said Jawad Nathem, 22. "Everything turned into dust and glass and shrapnel flew everywhere."
No one was hurt. "God saved us," Nathem said later from the damaged apartment on the 9th floor.
The U.N. team was invited by the Syrian government to discuss the terms of a possible inquiry into the alleged chemical weapons attacks.
Damascus has agreed that the U.N. investigate only one of the reported chemical weapons attacks — a March 19 incident in the northern village of Khan al-Assal in which rebels and the government accuse each other of using chemicals weapons — but rejected inquiries into other alleged attack sites in the central city of Homs, Damascus and elsewhere.
The U.S. and U.N. have called on Assad's regime to grant the United Nations team unfettered access to investigate all allegations of chemical weapon use.
Swedish chemical weapons expert Ake Sellstrom and U.N. disarmament chief Angela Kane arrived from neighboring Lebanon for a two-day visit, during which they are set to meet with senior Syrian officials, the U.N. said in a brief statement issued in the Syrian capital.
The Assad regime is said to have one of the world's largest stockpiles of chemical weapons, including the mustard gas and the nerve agent sarin.
There are concerns that Assad might use them on a large scale, transfer some of them to the Lebanese militant Hezbollah group or that the chemical agents could fall into the hands of al-Qaida militants and other extremists among the rebels.
Khan al-Assal, on the southwestern edge of the embattled city of Aleppo, was under government control in March but was captured by the rebels earlier this week. Even if the U.N. team is granted access to Khan al-Assal by both sides, it may be difficult to find evidence from the attack because so much time has passed.
In June, the United States said it had conclusive evidence that Assad's regime used chemical weapons against opposition forces. That crossed what President Barack Obama called a "red line," prompting a U.S. decision to begin arming rebel groups, although that has not happened yet.
On Tuesday, U.N. Mideast envoy Robert Serry told the Security Council that the U.N. has received 13 reports of alleged chemical weapons use in Syria. He said Sellstrom's team is studying this and other material.
Russia, Syria's close ally, has called the chemical weapons allegations against Assad's regime groundless, claiming Russian experts determined that Syrian rebels made sarin nerve gas and used it in the Khan al-Assal attack, in which 31 people died.
More than 93,000 people have been killed since the Syrian conflict started in March 2011, according to U.N. estimates.
In other violence Wednesday, state-run media said a volleyball coach who was a former national team player was killed in an ambush near Damascus.