China has beefed up security in Beijing and detained dozens of rights activists, lawyers and journalists ahead of the 25<sup>th anniversary of the Tiananmen Square massacre.

Additional security personnel have been deployed in the capital to prevent any unrest on the occasion, a day which China relentlessly tries to erase from history.

Checkpoints and pedestrian overpasses in the vicinity of the square are under the watch of police authorities and paramilitary troops.

A group called the Chinese Human Rights Defenders has said that more than 50 activists, who are critical of the Chinese government, are either missing or detained by the police.

"4 June has come again and the plainclothes officers are here to protect us. I can't leave the house to travel or lecture," Wu Lihong, an environmental activist said in a text message, according to the Associated Press.

Most of the detainees have been forced into a situation where authorities need not pursue legal procedures against them but keep them under a 24-hour watch.

Although such clampdowns are routine in China to suppress any information related to the Tiananmen Square bloodshed, this year the crackdown appears to be a bit harsher than usual, suggest reports.

Usually, the activists receive warnings on the anniversary, but now the authorities have a gone a step ahead by detaining several activists and opinion makers.

Foreign correspondents have also been reportedly warned by officials to tread carefully while covering issues linked to the Tiananmen anniversary.

The latest crackdown follows the arrest of Australian artist Guo Jian after his profile appeared in the Financial Times. He had depicted the massacre through a diorama of Tiananmen Square that he had covered in minced pork.