SINGAPORE, May 24 -- Vietnamese authorities apparently miscalculated during the protest targeting foreign enterprises in Vietnam last week, Li Mingjiang, associate professor at the S. Rajaratnam School of International Studies, Nanyang Technological University, said in a recent interview with Xinhua.

"They have, in some way, connived in the protest and the subsequent developments, but they apparently underestimated the possibility that the initially mild protests could turn violent," Li said.

Li said it's hardly likely for the violence to have been orchestrated in the way a color revolution was organized, given the abruptness of the riots breaking out. However, there had been signs that certain groups in the opposition were waiting for an opportunity to put pressure on the Vietnamese government.

The possibility cannot be ruled out that some Vietnamese-American groups have been behind the protest, he said.

"The territorial disputes between China and Vietnam provide them good excuses to organize such a kind of demonstrations, together with local NGOs within Vietnam," Li said. "The Vietnamese authorities, due to political considerations, chose to connive at these protests."

South China Morning Post reported recently that some theories in Vietnam implied outside influences behind the riots.

The violence went largely unchecked by Hanoi, at least at the initial stage. China evacuated thousands of its nationals from Vietnam after a few were killed and more than 100 others were injured during the violence.

Apart from the loss of investors from the Chinese mainland, quite a number of factories and companies from elsewhere, including China's Taiwan as well as South Korea, Japan and Singapore, were also victims of the violence.

Singapore's foreign ministry had voiced their "deep concerns" several times over the damages to two Vietnam-Singapore Industrial Parks in Binh Duong province.

A Singapore flag was burnt by demonstrators on May 13. Singapore's foreign ministry described it as "a serious incident." It had also urged Hanoi to immediately restore law and order before the security situation worsens and investor confidence is undermined.

The deadly violence, to some extent, can also be traced to the domestic challenges or the deteriorating relations between Vietnamese citizens and the government, as well as the worsened economic and social problems, Li said.

"The rioters broke into foreign factories, conducting wrecking, looting and setting fire, regardless of them being Chinese companies or not."