It is the first time since the executions, which were instrumental in leading to the imposition of sanctions on Nigeria, that commemorative activities have been allowed to take place.

Candle-lit vigil

The BBC Correspondent in Nigeria, Hillary Anderson, says that following an overnight candle-lit vigil, the streets are filled with people, most of them dressed in black. But, she says, no police and soldiers were to be seen, making this the first year that the government has not tried to stop the commemoration.

Ogoni activists have been calling on the government to release the bodies of Mr Saro-Wiwa and the others for a proper burial.

Shell given deadline

In a statement to coincide with the anniversary, the Movement for the Survival of Ogoni People (Mosop) gave the Anglo-Dutch oil company Shell a deadline to clean up its act.

"On the anniversary of the murder of nine of our leaders, Mosop presents Shell with a simple choice: Clean up the mess you have made by Ogoni Day - 4 January - 2000 or clear out once and for all."

Mr Saro-Wiwa led a movement for the improvement of minority rights, complaining about the environmental damage caused by the activities of foreign oil companies, particularly Shell.

Minority groups like the Ogonis, who live in the oil-rich Niger Delta, have been campaigning for a greater share of the oil wealth they believe is rightfully theirs.

The frustration felt by the Ogonis has now spread across the Niger Delta.