Nouakchott - African leaders issued a joint statement from a conference in Mauritania on Monday calling for the lifting of sanctions against Sudan, whose president is wanted for a string of atrocities.Omar al-Bashir, indicted for genocide in Sudan's western region of Darfur was among 11 leaders or government representatives at the meeting in Nouakchott of countries grouped by the "Great Green Wall" ecological initiative."For the sake of solidarity between the peoples of the member countries, the heads of state and government express their support for our sister republic of Sudan and call for the lifting of sanctions imposed on that country," they said in a joint statement. The Darfur conflict began in 2003 when black insurgents rose up against Bashir's Arab-dominated government, before Khartoum unleashed a bloody counter-insurgency, using the armed forces and allied militia.The United Nations says 300 000 people were killed in the conflict and another 2.5 million forced to flee their homes, and Sudan has been the subject of a variety of trade and arms embargoes supported by the international community.The leaders did not specify which sanctions they wanted lifted. Bashir arrived in Nouakchott on Sunday, despite an international arrest warrant issued against him in 2009 over charges of genocide, crimes against humanity and war crimes.Mauritania has not signed the Rome Statute of the International Criminal Court, however, and allowed him to visit without fear of arrest. Countries of the Sahel, which stretches from Mauritania in the west to Eritrea in the east, are signed up to a UN-backed plan to build a "Great Green Wall" of vegetation to halt the advance of the Sahara desert.The green wall will be around 15km deep and span more than 7 000km from Senegal to Djibouti.Experts estimate that Africa has lost around 650 000 square kilometres of productive land in the last 50 years, an area greater than the size of France.