Hong Kong director Johnnie To's latest movie on drug enforcement has wrapped up recently.

Known for his crime thrillers, such as Running out of Time and Election, To joined hands with the mainland studio Hairun to produce the film.

But To refuses to reveal the plot, saying he is still editing. The movie, tentatively entitled Drug War, was filmed in Hong Kong, Guangdong's provincial capital Guangzhou and Tianjin.

Hong Kong star Louis Koo and mainland veteran Sun Honglei, both experienced crime drama actors, lead the cast.