The ads try to portray the protests as "escalating violence" and call for "order to be restored," Engadget reported on Monday.
"Every day I go out and see stuff with my own eyes, and then I go to report it on Twitter and see promoted tweets saying the opposite of what I saw. Twitter is taking money from Chinese propaganda outfits and running these promoted tweets against the top Hong Kong protest hashtags," Pinboard tweeted.
Since June, Hong Kong has been rocked by a wave of protests because of the extradition bill, which would have enabled fugitives to be extradited from Hong Kong to mainland China.
Though the bill has been declared "dead" by the city's top leader Carrie Lam, the civil campaign against it has since morphed into a broader movement seeking to reverse a general decline in freedom and investigate police brutality.
A mass rally in Hong Kong on Sunday attracted tens of thousands of people as the crisis entered the 11th consecutive weekend of anti-government protests.
The "ads have highlighted alleged supporters of the Chinese 'motherland' and have pointed out Hong Kong's economic troubles from earlier in the year," the report said.
Twitter was yet to issue a statement.
The Chinese government has been clamping down on those who voice dissent on Twitter, even though the service is blocked beyond Hong Kong.
The recent wave of anti-government protests, sparked by a controversial extradition bill, has prompted widespread criticism of the police for their alleged brutality against protesters.
( With inputs from IANS )