A trio of plainclothes policemen in Vietnam's capital savagely attacked prominent blogger Trinh Anh Tuan on Wednesday, sending him to the hospital for treatment, he said, adding that they were among a group of men who have been observing his home for the past month. Tuan, better known by his online handle Gio Lang Thang, told RFA's Vietnamese Service that he had left his home in Hanoi at around 7:00 a.m. to carry out some errands for the family when he was accosted by the men wielding bricks. "About 500 meters (1,640 feet) from the house, there were three people on two motorbikes-they pushed me, making me fall down, and attacked me," said the blogger. "I ran away, but they chased after me, continuing to beat me-pushing me and hitting me in the head with bricks, causing me to bleed. I had to go to the hospital and received 10 stitches in my head, as well as some minor treatment to my hand," he said."I have scratches and bruises all over my body, arms, and legs. My body still aches." Tuan said that after returning from the hospital, he reported the incident to the police department in Long Bien district, where the attack occurred, and was told authorities would investigate. The blogger said he had "no conflicts with anybody," and that the attack appeared to be related to a group of people who had been monitoring his home and following him recently. "During the last month or so, there are always around 15 people guarding my house," Tuan said, though it was unclear why he was under surveillance. "I recognized the three attackers from among those people who are guarding my house," he said, adding that he believed the men were "disguised security personnel." Tuan, who operates a website calling for transparency from local officials with regards to a controversial tree removal plan in the city, said he had been harassed by plainclothes authorities before in March 2014, though "the injuries were not as severe as this time."He was also among 50 people detained and beaten by police on May 15 last year after taking part in an anti-China protest sparked by territorial tensions in the South China Sea. Bloggers targeted On Tuesday, independent U.S. monitor group The Committee to Protect Journalists (CPJ) ranked Vietnam as the world's sixth most censored country in its annual list based on analysis of media suppression tactics such as imprisonment or harassment of journalists, repressive laws and restrictions on the Internet. The report said independent bloggers who report on sensitive issues in one-party communist Vietnam-which it called one of the world's worst jailers of journalists-have faced persecution through street-level attacks, arbitrary arrests, surveillance, and harsh prison sentences for anti-state charges.Authorities increasingly used Article 258, an anti-state law that vaguely criminalizes "abusing democratic freedoms," to threaten and prosecute independent bloggers over the last year, it said. Shawn Crispin, senior Southeast Asia representative for CPJ, noted that at least three bloggers have been convicted under the law, which allows for seven-year prison sentences. "Now[the government is] using this new article, which is ... broad and vague, as a way of trying to stifle the limited amount of independent and critical journalism that is happening inside the country and this is increasingly being used against the bloggers who courageously report on issues that the mainstream state-controlled media do not," he said.