HONG KONG (Reuters) - Hong Kong has fallen into recession, hit by five months of anti-government protests that erupted in flames at the weekend, and is unlikely to achieve any growth this year, the city’s Financial Secretary said.

Black-clad and masked demonstrators set fire to shops and hurled petrol bombs at police on Sunday following a now-familiar pattern, with police responding with tear gas, water cannon and rubber bullets.

TV footage showed protesters, who streamed into the Kowloon hotel and shopping artery of Nathan Road on Sunday, setting fire to street barricades and squirting petrol from plastic bottles on to fires at subway entrances amid running battles with police.

At one station, activists rolled a flaming metal barrel down a long staircase toward police below.

“The blow (from the protests) to our economy is comprehensive,” Paul Chan said in a blog post, adding that a preliminary estimate for third-quarter GDP on Thursday would show two successive quarters of contraction - the technical definition of a recession.

He also said it would be “extremely difficult” to achieve the government’s pre-protest forecast of 0-1 % annual economic growth.

The rallying cry of Sunday’s protests was to fight perceived police brutality and defend Muslims and journalists. Police last weekend fired water cannon at a group of people standing outside a mosque and journalists have been wounded in clashes.

The programming staff union of public broadcaster RTHK said on Monday it had called on police to identify officers who “attacked and ripped the face mask” off one of its journalists on Sunday. It said she was wearing a reflective vest clearly identifying herself as a journalist.

Pictures circulating online suggested she was wearing a gas mask, to protect against tear gas and pepper spray. Ordinary face masks were banned this month under a resurrected colonial-era emergency law.

Hong Kong Free Press, an online news service, called for the release of a freelance photographer arrested on Sunday after she had asked to see a police officer’s warrant card.

The city’s Foreign Correspondents’ Club condemned the arrest in a statement calling for an independent investigation into “police violence against journalists and interference with the media’s right to cover the protests under Hong Kong law”.

The police, who deny using excessive force, told reporters they had repeatedly asked journalists to keep their distance so police can do their job.

They said an officer had removed a journalist’s mask, which had seemed an “undesirable” incident, but they said they did not know the full context. The Hong Kong Free Press reporter was arrested for failing to show ID and being uncooperative and obstructing police.

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Protesters have routinely torched store fronts and businesses including banks, particularly those owned by mainland Chinese companies and vandalized the city’s MTR Corp metro which has shut down services to stop protesters gathering.

The MTR has closed early for the past few weeks and said it will again shut down two hours early on Monday to repair damage.

Protesters are angry about what they view as increasing interference by Beijing in Hong Kong, which returned to Chinese rule in 1997 under a “one country, two systems” formula intended to guarantee freedoms not seen on the mainland.

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China denies meddling. It has accused foreign governments, including the United States and Britain, of stirring up trouble.

Tourists numbers have plummeted, with visitor numbers down nearly 50 percent in October, a decline Chan called an “emergency”.

Retail operators, from prime shopping malls to family-run businesses, have been forced to close for multiple days over the past few months.

While authorities have announced measures to support local small and medium seized enterprises, Chan said the measures could only “slightly reduce the pressure”.

“Let citizens return to normal life, let industry and commerce operate normally, and create more space for rational dialogue,” he wrote.