Voice on the streets

Tall and well built, 42-year-old Le Thien Nhan is a familiar face at anti-China protests. Wearing a smart lemon-yellow T-shirt emblazoned with the words "Hoang Sa Football Club" and a matching - although perhaps not deliberately - motorbike helmet, he is soon surrounded by police as we chat on the pavement.

"This has happened so many times. They have taken this measure repeatedly to stop protesters. They are protecting the Chinese Embassy, not the Vietnamese people," he says.

The Vietnamese government doesn't usually tolerate public demonstrations, and Nhan is among many regular protesters who are often closely monitored and harassed by police.

He is part of a tight-knit group of people from a wide variety of social backgrounds who try to express their feelings about what they see as China's aggressive actions in the South China Sea by taking to the streets.

Nhan and a group of friends formed the Hoang Sa Football Club as a way to express themselves without getting arrested.

But when China deployed an underwater drilling platform near the Paracel Islands - known as Hoang Sa in Vietnamese - earlier this month, emotions were running high and in an unusual move, the government allowed hundreds of people to take to the streets in protest.

However, days later, riots linked to the protests erupted in industrial parks with at least two Chinese workers killed. The government responded by shutting down the protests even in areas where they had been peaceful.

Police were sent to keep well-known activists at home, and security forces lined the streets outside the Chinese Embassy. Nhan says large groups of police were stationed outside his friends' homes to prevent them from joining the protest.

"A very large number of police, up to seven or eight were sent to the home of one person to stop them from demonstrating," he says. "I'm not like them as I have a wandering life. So, the police don't know where I am to detain me."

Police and security officials were everywhere, lining the pavement and lurking in vehicles on street corners. Large groups in green and blue uniforms were even waiting inside a cafe opposite the embassy.

While Nhan speaks, a large crowd of men gather around us, videoing our conversation.

"We are just peaceful demonstrators who come to raise our voices against China. But the police … many of these people who are filming us are policemen," he says.

Under police surveillance

As we chat, another group of policemen and women approach, some carrying megaphones telling people not to gather in the area. Nhan decides to make a move and disappears down the street on his motorbike.

Nearby is charismatic 72-year-old Cung Van, his thick black hair tucked under a red baseball cap commemorating the 50th anniversary of Vietnam's decisive victory against the French at the battle of Dien Bien Phu in 1954.

Ignoring the police megaphones he pauses to throw some victory signs for the cameras.

"I'm a musician and a colonel in the Vietnam People's Army. I come here to show my patriotism and attempt to chase the HD-981 oil rig away from our territorial waters," he says.

After retiring in 1992, Cung Van studied photography. He came with a camera so he could capture the moments, though not just for the aesthetics.

"If any ruffian attacks the demonstrators, I will try to capture the action to denounce them. They are the ones who need to be arrested," he says.

Unlike many of the other anti-China protesters, the retired colonel does not walk away when the police try to get him to move on. I ask him about his music, and when he starts talking, he is so at ease he could be sitting in his own living room.

"I wrote a song named 'Memory of the Village,' which is about my Thanh Tri rice noodle roll village. The second song is 'Glorious to the Vietnam People's Army,'" he says.

Marching on, regardless

The retired colonel says he is no stranger to the demonstrations, having participated in a similar protest in 2011.

"The people's demonstration to show patriotism and the Party's attempt to protect the nation do not contradict but support each other," he says. "What we have today was achieved by thousands of protests from 1930-1945. It's not right to tell protesters to let the Party do their business. There are many problems that the Party and the government must take care of, such as: preventing HIV and eliminating social evils. Why don't they take care of that?"

He finally moves away with the crowd. The police are getting more persistent and some protesters are beginning to leave, including writer Thuy Linh. With short cropped hair and a round face, she doesn't look her 55 years.

"I participated in almost every protest since 2011," she says as we walk. "I want to express my opinion about China's aggressive behavior. I think this is the responsibility of citizens when the country faces danger."

She says she has been to almost all the anti-China protests since 2011.

"Considering my age, my family doesn't stop me from doing this. Also, it's my personal right," she says. "Of course, I don't talk my relatives into joining me. But I have the right to be independent in my thoughts as well as my actions."

She soon disappears down a side street and the police continue to follow me. There are reports that several people have been detained in Hanoi and Ho Chi Minh City, but despite the crackdown, the intensity of emotion expressed by the people here suggests it will not be enough to send the protesters home for good.