A building housing Muslim pilgrims in the holy city of Mecca in Saudi Arabia has collapsed, killing at least 20 people and injuring nearly 60 others.

State television broadcast pictures of rescue workers using cranes and other equipment to sift through the rubble in a bid to save survivors. Witnesses say many of the casualties were pilgrims from Tunisia and the United Arab Emirates.

The building, which is used as a hostel during the hajj, is near Mecca's Great Mosque - Islam's holiest shrine. It was not immediately clear what caused the building to collapse.

About one million pilgrims have already arrived in Mecca for the annual hajj, but their numbers are expected to swell to more than two million by Sunday when the hajj begins.

Some information for this report provided by AFP and Reuters.