In the West African nation of Senegal, rap music has often been synonymous with freedom of speech. But many rappers are now afraid to express themselves because of threats of attacks from political and religious parties for writing critical lyrics.

At the top of a tower block in one of Dakar's tightly packed neighborhoods, a rapper/disc jockey known as Xuman broadcasts his daily radio show on a local radio station.

During a break for the news, the chart-topping dreadlocked rapper reminisces about events during the year 2000, when rap singers, sensing that Senegal's youth were tired of the Socialist party that had ruled the country for four decades, encouraged young people to vote for change.

"In the election time in 2000, we have maybe 5,000 rappers and half of them were rapping, 'this system must go.' So everybody was ready for revolution, a new system," he said. "They were telling the people, you want things to change? If you really want things to change, make a change. Go and vote, there is no other way."

For rappers like Xuman, the 2000 election was considered a triumph. The Socialist Party was voted out and the current president, Abdoulaye Wade, and his Senegalese Democratic party were voted in.

But despite the change in leadership, the last two years have seen a rise in violence against outspoken journalists, political activists and musicians in Senegal.

In May this year, a journalist was beaten by followers of a powerful marabout, or Muslim spiritual leader, for questioning his political influence.

In 2003, a French journalist was expelled from the country, accused of biased coverage of the rebellion-hit south.

Rappers have also been subjected to threats and violent attacks from the supporters of powerful religious or political figures.

Government officials have repeatedly denied democracy or freedom of speech is under threat in Senegal.

Still, rapper and radio personality Xuman talks about his fears under the new government.

"The difference between this system and the last is that now, people can beat you if you insult Wade, you will never get your video on the TV, on the radio, because the TV is for Wade. So rappers are singing about it but they are afraid, even if they cannot kill you, they are going do it to your family," he said.

Another of Senegal's top rap artists, Didier Awadi, sings about the problems facing ordinary people in Africa, and the failure of the president to do anything about them.

From his rooftop studio in Dakar, Awadi describes the despair he feels at the turn politics has taken in the last six years.

"For me things are getting worse, democracy is getting worse, there is no democracy anymore. For this new power, if you are not with them, you are against them," he said. "They are here because democracy worked, they have freedom of speech, today they are in power. So they must let this natural law rule. Senegal is used to this kind of thing, we need to talk, we need to express ourselves, but don't put us in jail because we don't like you."

With presidential elections looming in Senegal, some rap artists say they do not know if Dakar's rappers are ready to once more stand up for what they believe in.

But Awadi says he has sensed a renewed purpose within the rap movement in recent weeks. He says rappers seem to be more conscious of what he sees is a sense of despair among young Africans.

Awadi says rap music and its artists proved in the past to be an influential political force, and will be so again.