The emir of Qatar is reported to be about to change the succession in the conservative Gulf sheikhdom and name a crown prince.
There was no official explanation for the sudden change, but diplomats quoted by Reuters news agency said the current crown prince, Sheikh Jassim Bin Hamad Al Thani, was dissatisfied about not getting the responsibilities he had aimed for.
Qatar-based Al Jazeera television said the change would be announced on Tuesday.
Al-Jazeera said Sheikh Jassim was likely to be replaced by his brother Sheikh Tamim Bin Hamad, head of Qatar's Olympic committee.
Sheikh Jassim has been Qatar's crown prince since 1995 when his father the emir, Sheikh Hamad Bin Khalifa Al Thani, deposed his father in a bloodless palace coup.