BBC News with Michael Powles

President Zine El Abidine Ben Ali of Tunisia has announced that he'll not stand for re-election in 2014. The president, who has enjoyed almost unchallenged power for more than 20 years, was speaking as violent demonstrations against unemployment and falling living standards escalated and reached the centre of the capital Tunis. Here's our Middle East editor Magdi Abdelhadi.

In his third televised speech since the crisis began nearly a month ago, President Zine El Abidine Ben Ali offered major political concessions including a promise not to run for office again in three years' time. This is one of the key demands of the thousands of protesters who've taken to the streets across the country. Mr Ben Ali also said he has given orders to the security forces to stop using live ammunition against the demonstrators. He promised to reform the political system and allow the media to operate freely.