SINGAPORE - Some 30 companies signed letters of intent on Tuesday to invest in or work on the Eco Hi-tech Island, a China-Singapore joint venture project in the Chinese city of Nanjing.

The companies from China, Singapore, Germany, Japan, the United States and other countries signed the documents at a ceremony in Singapore.

The project is located on Jiangxinzhou, a small island on the Yangtze River 6.5 kilometers from the downtown area of Nanjing. The Singapore and China sides each held a stake of 50 percent.

Singapore's Minister of State for Trade and Industry Teo Ser Luck and Nanjing Mayor Ji Jianye officiated at the signing ceremony for documents on Tuesday.

Cooperation between China and Singapore has been growing fast over the past decades, with a number of flagship joint venture industrial parks in several cities from the coastal east to the inland west.