Iranian President Mahmoud Ahmadinejad has cancelled his trip to an African Union summit in Libya, officials in Tehran say. Mr Ahmadinejad's office did not give any reason for the decision. His visit would have been one of his first major public appearances abroad since his re-election in Iran's disputed poll last month. The opposition has staged mass protests, saying the poll was rigged. The authorities deny the claim. Some 17 people are thought to have died during opposition street rallies.