Dissident Ai Weiwei's Beijing studio demolished by Chinese authorities

Chinese artist Ai Weiwei says authorities have begun razing his Beijing studio.

The frequent government critic says on his Instagram account the demolition began Friday without prior notice and posted videos of an excavator smashing the windows of his "Zuoyou" studio.

"Today, they started to demolish my studio 'zuo you' ['left and right']" without notice, Ai wrote on Friday on the image-sharing platform, which is blocked by China's online "Great Firewall".

"Farewell," he wrote in English.

The studio in the northeast Beijing suburbs has been Ai's primary work space since 2006, although his has mostly been based in Europe in recent years.

It is Ai’s second studio to be torn down by Chinese authorities after one was demolished in Shanghai in 2011 without warning.

It's unclear whether the demolition is targeting Ai. Beijing authorities have demolished large swaths of the suburbs in the past year in a building safety campaign, typically giving at least several days' notice.

Ai, who has called attention to human rights violations and government corruption in China was detained for 81 days in 2011 amid a crackdown on government critics. 

His passport was confiscated for four years and he moved to Berlin after the travel document was returned to him in 2015.

Ai helped to design the Bird's Nest Olympic Stadium for the 2008 Beijing Games, but the artist's criticism of the Chinese leadership has made him a thorn in the government's side.