The African Union summit has opened in Libya with a call from the AU's top official to help Somalia's government.

AU Commission Chairman Jean Ping said Wednesday that the situation in Somalia warrants "special attention."

The Somali government is fighting Islamist insurgents who control large parts of the country.

The three-day summit in the city of Sirte will officially focus on Africa's economy and agriculture.  However, the gathered heads of state also are expected to discuss conflicts on the continent, such as the political crisis in Niger.

Two expected guests cancelled at the last minute - Iran's President Mahmoud Ahmadinejad and Italian Prime Minster Silvio Berlusconi.

Berlusconi canceled after a train crash that killed 16 people in western Italy.

Iran did not explain Mr. Ahmadinejad's absence, but delegates to the summit had expressed displeasure at his invitation, saying he would divert attention from African problems.

Another no-show Wednesday included Egyptian President Hosni Mubarak.

One leader who is in attendance is ousted Madagascar leader Marc Ravalomanana, who is seeking AU help to return him to power.

Mr. Ravalomanana was deposed from office in March, following weeks of opposition protests and a loss of military support.  The Indian Ocean island nation is now being run by military-backed former opposition leader Andry Rajoelina.

Some information for this report was provided by AFP and AP.