Two more Wal-Mart outlets in China have formed unions, bringing the total number of trade unions at the US retailer's stores in the country to four, state media reported Monday. Last Saturday, 31 employees at a Wal-Mart outlet in Nanjing, capital of Jiangsu Province, established the third union. A few hours later union number four sprung up in the southern city of Shenzhen, also home to the second union, which formed last Friday. The first union to be set up is based in a store in the southeastern province of Fujian. Wal-Mart has previously resisted calls for local unions at its 60 outlets in China. All such organizations are affiliated to the All-China Federation of Trade Unions, which was established by the Communist Party and is said to have 150 million members.