A liberal Muslim scholar in Egypt has drawn anger from religious leaders for saying smoking during the religious fast of Ramadan is allowed.
Smoking did not exist in Muhammad's time, the scholar says
During Ramadan, Muslims are banned from eating, drinking, smoking or having sex from dawn to dusk.
Egyptian scholar Gamal al-Banna disputed the no-smoking rule in a newspaper article, saying there was no basis in Sharia law for its banning.
But the orthodox view is Muslims should refrain from all pleasure in daylight.
Debate over tradition
Mr Banna, the brother of the founder of the influential Muslim Brotherhood, is a liberal scholar who has previously broken ranks with the orthodoxy on crucial matters, says the BBC's Arab affairs analyst Magdi Abdelhadi.
These have included capital punishment for apostasy, and wearing the veil.
He argues that consensus among scholars on the ban on smoking during Ramadan does not mean that it can not be re-examined.
Smoking does not need to be banned, because it did not exist at the time when the Prophet Muhammad was alive, he says.
Mr Banna's remarks have created debate over whether Islamic tradition can be reinterpreted, or Koranic laws questioned.
But strong reactions from religious leaders on what is considered a relatively minor issue shows those wanting to modernise Islam are facing an uphill struggle, our correspondent says.