NIAMEY, June 9 (Reuters) - Niger President Mamadou Tandja approved new Prime Minister Seyni Oumarou's cabinet on Saturday, reappointing the principal ministers just 10 days after a corruption scandal toppled the West African state's government. Oumarou took office this week after former prime minister Hama Amadou lost a no-confidence vote in the National Assembly of the landlocked former French colony. The opposition accused Amadou and his allies of complicity in embezzling hundreds of thousands of dollars in education funds, most of it from foreign donors. The opposition said it had declined an invitation to join the government from Oumarou, deputy head of the ruling National Movement for Society and Development (MNSD) party, because it suspected he could be linked to the corruption scandal. Oumarou does not face any charges in the embezzlement case. Niger's parliament voted in October to place two former education ministers on trial before the High Court of Justice in connection with the case. Both deny the accusations. Eighteen ministers retained their place in the 31-member cabinet according to a presidential decree on Saturday, including Economy and Finance Minister Ali Mahamane Lamine Zeine, Foreign Minister Aichatou Mindaoudou and Interior Minister Albade Abouba. Niger is the world's third largest uranium producer but the largely desert country had been dogged by coups, rebellions and droughts since independence from France in 1960. It is ranked as the world's poorest country by the United Nations in its human development index.