Chief Superintendent Tse Chun-chung of Hong Kong police's public relations branch displays seized weapons during a media briefing in south China's Hong Kong, Sept. 5, 2019. The Hong Kong police said four males were arrested Wednesday, bringing the total number of the arrested since June 9 to 1,187. (Xinhua/Qin Qing)

Chief Superintendent Tse Chun-chung (L) and senior superintendent Kong Wing-cheung of the Hong Kong police's public relations branch attend a media briefing in south China's Hong Kong, Sept. 5, 2019. The Hong Kong police said four males were arrested Wednesday, bringing the total number of the arrested since June 9 to 1,187. (Xinhua/Qin Qing)

The Hong Kong police said at a press conference on Thursday that the police officer injured in a knife attack a week ago is still being treated in ICU.

The off-duty officer, 45, was attacked by three males with a knife when he was walking past Kwai Yi Road around 11:15 p.m. local time on Aug. 30, sustaining injuries on his arms and back.

The possibility that the officer was attacked for personal reasons has been ruled out and he was most likely attacked randomly, the police said.

Chief Superintendent Tse Chun-chung of the Police Public Relations Branch warned that the violent acts against police officers have evolved from verbal abuses and telephone harassment to knife attacks and intimidation with suspected guns.

Hong Kong police shows footage of rioters disrupting public order during a media briefing in south China's Hong Kong, Sept. 5, 2019. The Hong Kong police said four males were arrested Wednesday, bringing the total number of the arrested since June 9 to 1,187. (Xinhua/Qin Qing)

Hong Kong police displays seized weapons during a media briefing in south China's Hong Kong, Sept. 5, 2019. The Hong Kong police said four males were arrested Wednesday, bringing the total number of the arrested since June 9 to 1,187. (Xinhua/Qin Qing)

The police will take maximum efforts to curb such violence, Tse said.

Another suspect was arrested Wednesday for assaulting a reporter from the Chinese mainland during an unlawful assembly at the airport over three weeks ago, according to the press conference. The male, charged with unlawful detention and unlawful assembly, has been taken to court.

As far, four suspects have been arrested for assaulting Fu Guohao, a journalist from the Beijing-based Global Times newspaper, during the violent incident at Hong Kong International Airport on Aug. 13.

The Hong Kong police also said four males were arrested Wednesday, bringing the total number of the arrested since June 9 to 1,187.

Violent incidents continued on Wednesday, with rioters destroying gate machines at Po Lam MTR station, pouring unknown liquid and covering the CCTV with plastic bags. A female passenger and an off-duty staff member of the subway operator were besieged and assaulted by the rioters.

Some radical protesters gathering outside the Mong Kok police station used laser pens to point at police officers and set up roadblocks to obstruct traffic on Wednesday evening.

Hong Kong police shows images of rioters disrupting public order during a media briefing in south China's Hong Kong, Sept. 5, 2019. The Hong Kong police said four males were arrested Wednesday, bringing the total number of the arrested since June 9 to 1,187. (Xinhua/Qin Qing)