A map of China is seen through a magnifying glass on a computer screen showing binary digits in Singapore in this January 2, 2014 photo illustration. REUTERS/Edgar Su

BEIJING (Reuters) - Some of China's largest Internet companies deleted more than 60,000 online accounts because their names did not conform to regulations due to take effect on Sunday, the top Internet regulator said.

Alibaba Group Holding Ltd, Tencent Holdings Ltd, Baidu Inc, Sina Corp affiliate Weibo Corp and other companies deleted the accounts in a cull aimed at "rectifying" online names, the Cyberspace Administration of China (CAC) said.

The reasons for their removal included accusations of being misleading, rumor mongering, links to terrorism, or involving violence, pornography and other violations, the CAC said in a statement on its website late on Thursday.

The purge is notable as a step toward China's government locking down control over people's internet account names, an effort which censors have struggled with in the past, despite numerous efforts to introduce controls.

These failed attempts have included trying to force users to register for online services using their real names.

The new regulations, which take on effect March 1 and will also target real-name registration, were issued by the CAC, which was formed last year and given power over all online content, something previously divided between various state ministries.

"Previously, the real-name registration system hasn't really been enforced," said Rogier Creemers, a researcher on Chinese media law at the University of Oxford. "These rules essentially impose a uniform and consolidated system for all online services requiring accounts."

The measure also reflects China's tightening control of the Internet, which has accelerated since President Xi Jinping took power in early 2013.

Weibo, the country's biggest microblog platform, will comply with the regulations and had a dedicated team to handle illegal information, including account names, a spokesman told Reuters.

E-commerce giant Alibaba declined to comment beyond highlighting a section of the CAC's statement on Alibaba's efforts to set up a team to handle account name issues. Tencent, China's biggest social networking and gaming company, and search leader Baidu were not available for immediate comment.

Among the accounts removed were those purporting to belong to state agencies, state media organizations and the East Turkestan Islamic Movement, said the CAC. China has blamed ETIM for violent attacks, but experts and rights groups have cast doubt on its existence as a cohesive group.

China operates one of the world's most sophisticated online censorship mechanisms, known as the Great Firewall. Censors keep a grip on what can be published online, particularly content seen as potentially undermining the ruling Communist Party.

(Reporting by Paul Carsten; Editing by Robert Birsel)