DAMASCUS, Syria (AP) — A U.N. delegation tasked with investigating the reported use of chemical weapons in the Syrian conflict arrived in Damascus today to discuss terms of a possible probe into alleged attacks.

This is the first such trip by international experts and the talks are expected to focus on about a dozen incidents in which chemical weapons were allegedly used. The rebels, the U.S. and others have blamed the regime for attacks, while Damascus and its ally Russia say the rebels have used chemicals.

Damascus has requested the U.N. to investigate one of the reported attacks — a March 19 incident in the northern village of Khan al- Assal in which both rebels and the government accuse each other of using chemicals — but refused inquiries at other alleged attack sites in the central city of Homs, Damascus and elsewhere.