Protesters shout anti-China slogans as they hold up marked depictions of Chinese president Xi Jinping at Lenin park in front of the Chinese embassy in downtown Hanoi on November 5, 2015.
Chinese President Xi Jinping arrived in Hanoi today for a visit that has drawn the ire of Vietnamese nationalists at a time of bubbling conflict over disputed territory in the South China Sea.
The communist neighbours have long celebrated their political and economic ties but in recent years tensions have flared over a decades-old feud about island chains in the contested waters.
Hours before Xi's visit -- the first by a Chinese president to Vietnam in 10 years -- anti-China activists staged small but rare protests in the heart of the Vietnamese capital and southern Ho Chi Minh City.
"Protesting Xi Jinping's visit", said one of the placards held aloft by about a dozen demonstrators in Hanoi, as others carried pictures of Xi marked with an "X".
But unlike protests earlier this week, they were quickly disbanded, witnesses told AFP, saying demonstrators in the capital were funnelled into buses and driven away.
In Ho Chi Minh City social media reports said around 20 people were detained after a larger anti-China protest with a video showing a bloodied demonstrator following clashes with police.
Rallies are rare in authoritarian Vietnam but the ruling regime has in recent years tolerated low levels of dissent against its main ally China.
Anger against Xi's visit has also been brewing online -- a more common outlet for grievances despite the routine arrests of political bloggers.
"Immediately end activities which threaten the lives, property and right to freedom" of Vietnamese fishermen, said a petition signed by hundreds and shared on Facebook, referring to the disputed isles.
Relations between Vietnam and China plummeted to their lowest point in decades in May 2014 when Beijing moved an oil rig into waters claimed by Hanoi in the contested South China Sea.
The anti-China riots that ensued targeted foreign-invested factories and saw the Asian giant evacuate thousands of its nationals after at least three Chinese were killed.
Patriotic sentiments still run high in Vietnam, and Xi's visit is being viewed by some observers as an attempt to improve relations after that episode.
He "aims to calm down Vietnam and other countries over the recent construction by China" in the South China Sea, said Duong Danh Dy, a former Vietnamese diplomat in Beijing.
Xi is scheduled to meet ruling Communist Party chief Nguyen Phu Trong, President Truong Tan Sang and Prime Minister Nguyen Tan Dung during his two-day trip.
'Territorial dispute'Last week Chinese officials told reporters in Beijing that the territorial dispute would be discussed as well as cooperation on trade, education and infrastructure.
China lays claim to almost all of the South China Sea, parts of which are also claimed by the Philippines, Brunei, Malaysia and Taiwan as well as Vietnam.
Japan and China are also locked in a row over disputed islands in the East China Sea.
In recent months Vietnam has been trying to strengthen bonds with other nations to counter China's growing regional prowess.
Communist Party general secretary Trong was received by US President Barack Obama in July, the first party chief to visit the country and the White House.
Vietnam is also party to the recently sealed Trans-Pacific Partnership, the world's largest free trade deal between 12 nations including the US and Japan but not Beijing. The TPP is viewed by some as a counterbalance to growing Chinese economic clout.
In a separate visit, Japanese Defence Minister Gen Nakatani will also be in Vietnam during Xi's trip. He is due to tour a strategic naval base on Thursday in central Vietnam, according to Vietnamese state media.
Despite their political closeness, Vietnam and China fought a brief but bloody war in 1979 triggered by Hanoi's invasion of Cambodia.