Tunisian President Zine El Abidine Ben Ali has dismissed his interior minister. He also ordered the release of all of those detained during the recent unrest triggered by unemployment and high food prices.At a news conference on Wednesday, Prime Minister Mohamed Ghannouchi revealed that the president had decided to replace Rafik Belhaj Kacem, who was responsible for the much-criticised police force.He said Ahmed Friaa will replace Belhaj Kacem at the interior ministry.Earlier, troops were deployed in the capital after fresh protests about unemployment and poverty in a suburb.Officials say 21 people have been killed since the protests began in the south of the country in mid-December, but human rights and trade union activists believe the number of dead to be at least 50.People taking part in the demonstrations say they are angry about unemployment, poverty, corruption and government repression.President Ben Ali has said the riots are a terrorist act orchestrated by foreign forces to damage Tunisia.