Hong Kong police launched an investigation on Monday into twin attacks on premises owned by pro-democracy media magnate Jimmy Lai.

Firebombs were thrown at his house and offices in what is believed to be an attempt to intimidate the outspoken billionaire.

Surveillance video at Lai's home showed a car backing up to the gates and a masked attacker throwing what appeared to be a Molotov cocktail before driving off.

At around the same time early Monday, another device was thrown from another vehicle at the entrance to his Next Media company. Its publications include the flagship pro-democracy Apple Daily, which is one of the city's most popular newspapers.

There were no reports of injuries in either incident.

Local media said the cars used in the attacks were later found burned out and stripped of their license plates.

Media tycoon's anti-Beijing stance

Jimmy Lai is known as a critic of Beijing and has openly voiced his support for Hong Kong's pro-democracy movement.

Activists occupied key areas of the semi-autonomous southern Chinese city for more than two months to demand free and fair leadership elections without Bejing vetting candidates in advance.

Lai was among thousands of protesters who were tear-gassed by police as the protest movement erupted in September. The demonstrations ended when rally camps were cleared in December.

He was arrested during the clearance of the main Admiralty site and has been asked to appear at a police station later this month.

Lai stepped down as chairman of Next Media following his arrest saying he wanted to spend more time with his family.

"The goal is intimidation," said Next Media spokesman Mark Simon of Monday's attacks.

He said they were a "continuation of the attacks against Lai and Next Media for its editorial position, which is at odds with the anti-democracy forces."

The AFP news agency quoted the Hong Kong police who said the incidents had been classed as "arson attacks."

lw/bw (AP, Reuters, AFP)