Syria has agreed to allow U.N. inspectors to visit three sites to investigate accusations  of chemical weapons use, the United Nations said Wednesday.
The sites include Khan al-Assal, the northern town at the center of rival chemical weapons accusations where fighting between government troops and rebels raged Wednesday.
The head of a U.N. chemical arms probe team, Ake Sellstrom, and the head of the U.N. Office of Disarmament Affairs, Angela Kane, visited Damascus last week at the invitation of the Syrian government to discuss access.
“On the basis of the information evaluated by the Mission to date and further to the understanding reached with the government of Syria, the Mission will travel to Syria as soon as possible  to contemporaneously investigate three of the reported incidents, including Khan al-Assal,” U.N. Secretary-General Ban Ki-moon’s press office said in a statement.
Damascus had refused to let U.N. investigators go anywhere except Khan al-Assal in Aleppo province, where Syrian President Bashar Assad’s government and its ally Russia say rebels used chemical weapons in March.
Fierce fighting erupted on the outskirts of the town Wednesday, which the rebels seized on July 22, inflicting heavy losses on the army, the opposition-aligned Syrian Observatory for Human Rights reported.
The Syrian army lost 150 soldiers over two days, 50 of them summarily executed after their capture, in an act condemned by the mainstream opposition leadership.
The United Nations did not identify the other two locations to be visited by investigators but diplomats identified them as Ataybah near Damascus, where a suspected attack was staged in March, and Homs, where chemical weapons are alleged to have been used  on Dec. 23, diplomats said.
Britain and France have submitted evidence to the United Nations on the Ataybah and Homs attacks, which they say was carried out by the government.
Both sides deny using chemical weapons. The U.N. has received 13 reports of alleged chemical weapons use in Syria  and will only try to establish whether chemical weapons were used, not who used them.
The visit comes as Assad’s forces appear to be building on gains against rebels in the country, pushing to regain rebel-held areas of the Damascus Countryside and central Homs.
The oil refinery of the central city of Homs came under fire Wednesday for the second time in a week, the Observatory said. Several of the refinery’s staff were wounded by “terrorist rocket fire,” the state SANA news agency said.
Meanwhile six workers of a “scientific research center” – or military research facility linked to the Defense Ministry – in Barzeh, a district of north Damascus, were killed and 19 wounded when rebels fired a mortar round at their bus, SANA said.
The Observatory gave a casualty toll of four dead and 20 wounded.
It also reported that two local dignitaries who have often served as mediators between rebels and loyalist forces were gunned down Tuesday night in the northwestern city of Zabadani.
And in eastern Syria, where clashes between jihadists and Kurdish fighters have raged for some two weeks, the Observatory reported that jihadist groups linked to Al-Qaeda have taken hostage around 200 Kurdish civilians.“Fighters of Al-Nusra Front and the Islamic State of Iraq and Syria have seized control of Tall Aren village in Aleppo province and are laying siege to another village nearby, Tall Hassel,” it said. “They have taken hostage around 200 civilians from the inhabitants of the two villages.”
Syria’s main Kurdish militia issued Tuesday a call to arms to battle jihadists , hours after a Kurdish leader, Issa Hesso was killed following weeks of clashes between the minority group and radical Islamists.
“We call on the Kurdish people ... to step forward ... anyone fit to bear arms should join the ranks of the Committees for the Protection of the Kurdish People and to face the assaults of these [jihadist] armed groups,” a statement from the Committees said.