A UN official says that more than 8,000 people have died since anti-government protests erupted in Syria a year ago.
UN General Assembly President Nassir Abdulaziz al-Nasser said many women and children were among the victims.
His comments come as the UN and Arab League envoy to Syria, Kofi Annan, is to meet Syrian opposition in Turkey.
But after yesterday's talks with Turkey Prime Minister Recep Tayyip Erdogan in Ankara, Annan admitted that the diplomatic process would take time, describing the situation in Syria as "very complex".
Annan is due to meet members of the opposition Syrian National Council in Turkey shortly.