HO CHI MINH CITY, July 6 (Xinhua) -- Police of Vietnam's Ho Chi Minh City have arrested seven local people after seizing TNT explosives during a raid.

Four people are being held on suspicion of conducting terrorist activities, and three others in connection with the illegal trading of explosives, local daily newspaper Vietnam News reported Friday.

According to Phan Anh Minh, deputy chief of the municipal police, a big explosion occurred on June 20 at a police station in Tan Binh district, injuring one police officer and damaging property.

After more than 10 days of investigation, the city's police, in coordination with their counterparts from the neighboring province of Dong Nai, arrested seven suspects, and seized nearly 10 kg of TNT explosives, as well as other materials used to make bombs for similar attacks.