The two explosions went off 20 minutes apart inside two cinemas at two malls after 9 p.m., Xinhua reported.
The first blast hit the sprawling SM City Davao in Matina and the second in Gaisano Mall in Bajada, which are about 10 km apart.
Those injured by shockwaves were movie patrons, police said.
The bombs were only meant to scare people and not really intended to cause injuries, as there were no shrapnels found, police said.
--IANS (Posted on 17-09-2013)