Chinese authorities have tightened security around Beijing's iconic Tiananmen Square on the 27th anniversary of the bloody military crackdown on student-led pro-democracy protests.

Police on Saturday checked IDs and searched the bags of anyone seeking to enter the environs of the vast public space where thousands of students, workers and ordinary citizens gathered in 1989 to demand political reforms. Journalists from The Associated Press were stopped, filmed and ultimately forced to leave the area, ostensibly for lacking proper permission.

The heightened security points to the ruling Communist Party's continuing sensitivity over the events, which remain a taboo topic within China. Hundreds, possibly thousands, were killed as tanks and troops converged on Beijing on the night of June 3-4, 1989. Any form of commemoration, whether public or private, is banned.