Banki moon
UN chief tells African leaders not to 'cling to power'
It echoed remarks made by US President Barack Obama in the same AU hall on a trip to Ethiopia in July.
The opposition says the international community now realises that Assad cannot stay in power.
UN Secretary-General Ban Ki-moon opened proceedings at Montreux on Lake Geneva.
The peace talks set to begin on Wednesday will include the first talks between Assad and his opponents.
The UN weapons inspection team has pulled out of Syria.
Phumzile Mlambo-Ngcuka was sworn in as the new head of UN Women on Monday.
Reports suggest the country has taken two Musudan missiles off launch-ready status.
The United States encourages United Nations members to lift arms embargo on Somalia.
UN Secretary-General Ban Ki-moon recommended "offensive military operations" in Mali.
An internal review panel says the UN failed to pay proper attention to the war torn country.