As thousands of Syrians fled their conflict-ridden homeland into northern Iraq, a long-awaited team of United Nations chemical weapon investigators led by Swedish scientist Ake Sellstrom reached Damascus on Sunday.

A Free Syrian Army fighter wearing a gas mask carries his weapons as he walks past a damaged tank, after seizing a government military camp used by forces loyal to Syria's President Bashar al-Assad, near Idlib. (Reuters)

Limited Mandate

The mandate of the investigation is to determine whether chemical weapons were actually used in the conflict. In case evidence is found, the team will focus on ascertaining the type of weapons used. It would, however, not assign the blame for its use.

Months of Negotiations

The visit of the investigation team follows month of negotiations over the sites they could visit. The UN sought full access, a demand that was rejected by the Assad government. They finally agreed to allow the UN investigators to visit three sites that included Khan al-Assal and two other undisclosed locations.

Three Years of Conflict, 100,000 Dead and Counting

A reported chemical weapon attack had killed dozens of people in the village of Khan al-Assal, near the northern city of Aleppo on March 19. Several other cases of its use have surfaced in the civil conflict which is now in its third year and has left more than 100,000 people dead and many more as refugees.

However, many in the opposition have already questioned the effectiveness of the UN investigation team. They point out that a similar mission by the UN last year had failed to broker a negotiated settlement to the conflict.

Though the UN team did not comment on their arrival in Damascus, the Syrian government has said it will cooperate with the investigation.

US-Russia Confrontation

Allegations of chemical weapon use are a major issue in the conflict. Forces loyal to beleaguered President Bashar al-Assad and rebel have accused each other of chemical weapons use. It has also led to a tiff between the U.S. and Russia which backs the Assad government.

Last year, President Obama declared the use of chemical weapons as a "red line" which could lead to US military intervention in the conflict.

In June this year, U.S. officials had alleged that Assad's forces had used chemical weapons "on a small scale against the opposition multiple times in the last year". Following U.S. allegations, Russia had accused rebel fighters of using the weapons in Khan al-Assal.