TIANJIN, July 4 (Xinhua) -- The Tianjin-Taiwan trade fair opened Thursday in northern China's Tianjin municipality, highlighting cooperation and communication.

The four-day event attracted about 600 companies from Taiwan, which brought products including food, tea, jewelry and farm produce to the fair, according to Tianjin's Taiwan affairs office.

Liu Jieyi, director of the Taiwan Work Office of the Communist Party of China Central Committee and the Taiwan Affairs Office of the State Council, said there were over 4 million cross-Strait visits in the first five months, up about 10 percent year on year.

He said the mainland will offer thousands of internship opportunities for Taiwan compatriots this summer.

Chiang Hsiao-yen, former vice chairman of the Chinese Kuomintang Party, said the mainland has done a lot to protect the rights and interests of Taiwan business people, who in turn has made contributions to the economic development and vitality of the mainland.

People of both sides across the Taiwan Strait belong to the same family and they should cooperate, Jiang said.

A fair promoting cross-Strait investment also started in Tianjin on the same day.

More than 2,300 people from all walks of life in Taiwan have attended the annual trade fair since 2008. The investment fair, which has been held since 2010, has attracted 3.6 million buyers.