* Three dead, hundreds wounded in ongoing clashes
* Tensions soaring ahead of legislative elections
* Guinea is world's No. 1 bauxite supplier
By Saliou Samb
CONAKRY, March 2 (Reuters) - At least one person was killed by gunfire and three others injured in ongoing street clashes in Guinea on Saturday, and the government said it was investigating whether security forces used live rounds against civilians.
Two civilians and one police officer have been killed and hundreds of people injured since tensions over upcoming legislative polls triggered unrest in the West African nation's capital Conakry last week.
Much of the violence has been between rock-throwing demonstrators and security forces using tear gas and wielding truncheons, though witnesses said police were also firing guns in an effort to disperse protesters.
"We have heard of four people injured by bullets today, and one of them has died," said government spokesman Damantang Camara. "We are now investigating where these shots came from."
Long-delayed elections due in May are meant to complete a transition to civilian rule after a 2008 coup, and could open the door to hundreds of millions of dollars in European aid.
But preparations for the legislative poll have been hampered by opposition claims the government is seeking to rig the outcome in advance, leading to a political impasse and sparking sporadic street protests that often turn violent.
Politics in Guinea, the top world supplier of bauxite, raw material of aluminium, are mainly drawn along ethnic lines. The opposition coalition is broadly supported by the Peul, the biggest ethnic group, and the government by the Malinke.
Guinea's notoriously ill-disciplined security forces have a history of brutal crackdowns on protests, though the government has launched a U.N.-backed effort to professionalise them..
One of the wounded told Reuters on Saturday he was shot by a member of the security forces while he was trying to run away.
"I tried to run and he fired," Ibrahima Diallo said at a private clinic where he was seeking treatment.
Security forces in riot gear patrolled in pickup trucks and deployed on street corners on Saturday.
The violence, which began on Wednesday after opposition supporters clashed with police, has left a wake of burned-out shops and vehicles and spent tear gas cannisters. By Friday, rival ethnic gangs battled in the ramshackle city using machetes, knives and clubs, witnesses said.
Guinean President Alpha Conde appealed for calm late on Friday and urged opposition leaders to do the same.
"All sides must avoid provocation, personal vengeance and taking justice into their own hands," Conde said in a televised address. "I ask religious leaders, security forces, elected officials and political leaders to call for calm."
Conde narrowly won a 2010 presidential election - billed as the former French colony's first free poll since 1958 independence - promising to unite Guinea in the same way Nelson Mandela did after apartheid in South Africa. (Writing by Richard Valdmanis; Editing by Jason Webb)