Hanoi - Police in the port town of Ha Long City have identified and are pursuing several suspects who they allege killed six people and wounded one this week in a dispute over coal smuggling, a police official said Thursday.

The victims were shot early Monday in Ha Long City harbour. Police spokesman Nguyen Trinh Dong said police had not yet captured any of the suspects.

Dong said police had determined the killings stemmed from a conflict between two groups competing to smuggle coal from illegal unlicensed mines to nearby China.

Police believe ringleader Pham Huy Nam, 33, alias Nam Bang, ordered his men to kill anyone exploiting coal without his permission in areas he claims to control.

The victims in the shootings on Monday were reportedly coal diggers under the protection of the leader of another Ha Long City coal smuggling gang, who goes by the alias Tam Trong.

Local media reported Thursday that the illegal coal mining areas controlled by Trong had shrunk after provincial police began a campaign early this year to restrict the trade. Trong and Bang's associates have reportedly been fighting over control of the remaining mining areas ever since.

According to the local press, Trong sent subordinates on Monday morning to steal 10 tons of coal that Bang's men had piled in a harbour area they control, awaiting shipment. As Trong's men were transferring the coal to one of his ships, Bang's men arrived and warned them to stop, but were ignored.

Bang's men then reportedly ambushed Trong's team as they left the site on motorbikes. Police said the guns used were most likely modified bird-hunting guns or small Chinese guns sold as toys.

One of Trong's men, Le Ba Chung, 23, was hit by 3 bullets but survived, and is being treated in a hospital under police supervision.

Among the dead were two students, Nguyen Van Hien, 15, and Pham Dinh Hiep, 21, who had come home from Hanoi for the weekend.

Local media Thursday quoted Quang Ninh provincial chairman Vu Duc Dam as denying that the killings were related to "criminal gangs." But police acknowledged they had resulted from conflicts between groups engaged in persistent illegal activities.

Police spokesman Dong said he "found it hard" to provide "a clear definition of what is a criminal gang." (dpa)