On Monday, police were seen stopping a film crew from a Spanish television network and asking them to leave the square.
Internet access was also limited across the mainland, with Twitter, a social networking service, and Hotmail email accounts being blocked on Tuesday.
|Increased restrictons have been reported by locals and foreigners [Reuters]
Prominent dissidents and activists who took part in the protests have also reported increased restrictions on their activities, with some even being taken out of Beijing.
On Tuesday New York-based rights group Human Rights in China said Wu Gaoxing, a former political prisoner, had been taken from his home in the eastern city of Taizhou.
Wu's arrest came shortly after the publication of a letter he had co-signed complaining about economic discrimination against dissidents.
The crackdown on the Tiananmen square protests was one of the bloodiest episodes in recent Chinese history but is virtually ignored in the tightly-controlled state media.
On the night of June 3-4, 1989, the Chinese government ordered the military to forcibly end the demonstrations.
Violent clashes ensued and the number of people killed remains unknown.
The government's official death toll stands at 241, including 36 students. But activists say thousands may have died.
Many young Chinese today say they have not heard of the demonstrations because they cannot find any records of it.
However, public commemorations are planned, with a "silent protest" being organised for Thursday.
Activist groups have called on ordinary Chinese to wear white - the traditional colour of mourning - aimed at honouring those killed.
At the weekend one of the few public commemorations on Chinese soil was held in central Hong Kong.
Hundreds of demonstrators marched through the city on Sunday while tens of thousands of people are expected to attend a candlelit vigil on Thursday.
|Hundreds marched in Hong Kong on Sunday to mark the upcoming anniversary [Reuters]
The 1989 crackdown prompted years of international criticism of China's domestic policies and its human rights record.
But China's rapid economic rise and its transformation into the world's third largest economy has long since seen it welcomed back into the fold.
At the same time however China's communist leaders have shown no willingness to change their position that the Tiananmen protests threatened their rule and had to be quelled in order to maintain economic reforms.
Bao Tong - a former aide to Zhao Ziyang, the then Communist party secretary-general, who was jailed for seven years following the crackdown - said the world has failed to push China to be more open about the events of Tiananmen because of Beijing's increasing global influence.
"Not wanting to offend China means they cannot help China, cannot help China's people attain their own rights, and cannot help the world community gain a reliable, stable, peaceful member," he told AFP.
But activists say the Chinese public could yet hold the government accountable.
"People remember this date because they want the Communist Party to take responsibility for the crimes it committed," Qi Zhiyong, a protestor who lost a leg after being shot by troops during the crackdown, told AFP.
"It reminds them the party will resort to unbridled violence whenever it feels threatened."