HONG KONG — Google, fresh off a dispute with China over censorship and intrusion from hackers, says it has identified cyber-attacks aimed at silencing critics of a controversial, Chinese-backed bauxite mining project in Vietnam.

In attacks it described as similar to but less sophisticated than those at the core of its spat with China, Google said malicious software was used to infect “potentially tens of thousands of computers,” broadly targeting Vietnamese speaking computer users around the world.

Infected machines had been used to spy on their owners and to attack blogs containing messages of political dissent, wrote Neel Mehta of the company’s security team in a post late Tuesday on Google’s online security blog.

McAfee, the computer security firm, said in a separate blog posting that it believed “the perpetrators may have political motivations and may have some allegiance to the government of the Socialist Republic of Vietnam.”