Kofi Annan, the UN-Arab League envoy to Syria, will head to Tehran on April 11, a day after Syria is expected to have withdrawn troops from all populated areas, his spokesman said Thursday.

"Mr Annan will be visiting Tehran on the 11th," he said. Iran is an ally of Syria, and its supreme leader Ayatollah Ali Khamenei has pledged to defend the government of Bashar al-Assad. [AFP]