CONAKRY, June 6 (Reuters) - Striking employees of Russian aluminium giant Rusal's Guinea subsidiary Compagnie des Bauxites de Dian-Dian (COBAD) returned to work on June 2, one week after their protest action started, a union leader said on Monday.

The workers at COBAD went on strike on May 26 to demand better pay and conditions.

"We obtained a 5% increase on our base salary, housing allowance and guarantees for medical treatment," union leader Yamoussa Bangoura told Reuters.

Rusal did not immediately respond to a request for comment.

Guinea is the world's second-largest producer of bauxite, an ore used to make aluminium, and a key supplier of bauxite to China. It produced 83 million tonnes of bauxite in 2021, Guinea's mines ministry statistics showed.

COBAD produced 3.59 million tonnes of bauxite last year, while Rusal's other Guinea operation, Compagnie des Bauxites de Kindia, produced 2.65 million tonnes, according to the mines ministry.

(Reporting by Saliou Samb; Additional reporting by Helen Reid; Writing by Sofia Christensen; Editing by Lisa Shumaker)