Senegalese police fired tear gas and chased protesters from the centre of the West African nation's capital Saturday in a fourth day of protest against the candidacy of incumbent President Abdoulaye Wade in the February 26 presidential poll.

As about 23,000 security personnel including the police and army voted in early balloting Saturday, protesters took to the streets, strewn with debris from the previous night's protest, setting up barricades, burning tyres and trash, and clashing with riot police.

The protesters are trying to gain access to Dakar's Independence Square, near the presidential palace, but have been pushed back by riot police using tear gas and water cannons.

The government has banned all opposition protest around the square citing security reasons.

Opposition leaders and civil society group M-23 have vowed to make the country ungovernable if Wade does not step down and withdraw his bid to seek a third term, arguing that his bid breaches rules setting a two-term presidential limit.

Authorities said a 21-year-old tailor died in the city of Kaolack, about 190 km (125 miles) southeast of Dakar, from wounds he suffered during a protest Friday.

At least five people have been killed in street clashes since last month when Wade's candidacy was validated by the country's top legal body. World leaders have called on all sides to show restraint, warning the West African nation's democratic credentials are at stake.

Leaders of the West African regional bloc ECOWAS, meeting in Nigeria Friday, said they would send a joint mission with the African Union, headed by former Nigerian President Olusegun Obasanjo, to engage Senegalese politicians in dialogue.

I'm counting on President Obasanjo to come and look at President Wade eye-to-eye and tell him that at nearly 90 years old, it is time to retire, said Cheikh Tidiane Gadio, a former foreign minister in Wade's government who is one of the 13 candidates in the presidential poll.

(Writing by Bate Felix; Editing by Janet Lawrence)