A Lotte Mart is seen closed in Jiaxing, East China's Zhejiang province, Sept 8, 2017. [Photo/Agencies]

South Korea's Lotte Group has begun steps to sell its discount store chain in China due to plummeting sales, Yonhap News Agency reported on Thursday, citing company officials and an industry source.

The group is reportedly in talks to sell all of its China stores and has appointed Goldman Sachs to manage the sale.

So far, 87 out of the 112 Lotte Mart stores in China have been closed for over six months.

In March, Chinese customers protested against the conglomerate's role in the deployment of the controversial THAAD anti-missile shield.

The Chinese Foreign Ministry said it was up to consumers to decide whether international companies were successful in China or not.