A UN team arrived Sunday in Damascus to investigate alleged use of chemicals weapons in Syria's 29-month civil war, dpa quoted local sources as saying. The 20-member UN group, headed by Swede Ake Sellstrom, was expected to inspect three sites in the country. The Syrian opposition National Coalition has criticized reported limits on the team's activities, saying it risks missing evidence that such weapons were used in other areas, including on the outskirts of Damascus. A spokesman for UN Secretary General Ban Ki-moon announced Wednesday that the Syrian government had agreed to "modalities" for the mission, paving the way for its departure after lengthy delays. The UN inspectors were authorized to make on-site visits and may remain in Syria up to 14 days. The investigation period could be extended by mutual consent. In recent months, Britain, France and the United States have presented evidence of suspected chemical attacks in Syria, which they blamed on troops of President Bashar al-Assad. US President Barack Obama warned al-Assad that use of chemical weapons would constitute the crossing of a "red line" and would result in "enormous consequences." But there has been no Western intervention in the Syrian conflict, which has killed more than 100,000 people, according to the United Nations.