Vietnam pledged on Saturday to quell any outbreak of violence after protests against Beijing this week devastated key industrial centers, due to discontent with the Asian giant oil drilling in a disputed area in the South China Sea South. The principal investigator of the Vietnamese police defended the security forces, accused of failing to control disorder and said "illegal acts" will not tolerate a day before planned protests against China in its major cities. Hoang Kong Tu said to the media that the authorities would apply the full force of the law and that the violence Tuesday and Wednesday would not be repeated, when groups of protesters attacked industrial parks in three provinces vital for the economy and exports Vietnamese.