Photo taken on Aug 2, 2014 shows the workshop where a powerful blast happened in Kunshan, East China's Jiangsu province. [Photo/Xinhua] More photos

BEIJING - Chinese President Xi Jinping has ordered all-out efforts to treat the injured and comfort the families of the dead after a factory blast on Saturday.

Massive factory blast kills 68 in E China?

The explosion, which happened at 7:37 am, killed 69 people and injured more than 150 others after ripping through a factory in East China's Jiangsu province.

More than 200 workers were on the site when it happened.

Xi has demanded a full investigation into the incident and harsh punishments for those responsible.

Premier Li Keqiang has ordered safety checks to avoid similar tragedies from happening again.

Local officials said the explosion was a work safety accident, and the blast was probably caused by flames igniting dust inside the workshop.

Two senior executives at Kunshan Zhongrong Metal Products Co., Ltd have been placed under police custody.

President Xi and Premier Li have assigned state councilor Wang Yong to lead a State Council working team to Kunshan to look into the accident.

Local health authorities said most of the injured suffered burns and have been treated in hospitals in Kunshan and the nearby cities of Suzhou, Wuxi and Shanghai.