A monk consoles relatives of one of the hostages killed in the bus siege during a Buddhist religious ceremony at the site of the hostage taking in Manila on Tuesday.

A total of 18 condolence points across Hong Kong, together with a dedicated facebook page, were set up by the city's government on Tuesday, allowing residents to mourn eight Hong Kong victims of the hostage-taking incident in the Philippine capital Manila.

Hong Kong Chief Executive Donald Tsang visited one of the condolence points set up at Leighton Hill Community Hall in Wan Chai on the Hong Kong Island, where he led others to observe a one- minute silence and presented a bouquet of flowers for the eight slain Hong Kong tourists.

"The Hong Kong people will remember you forever," a gravely- looking Tsang wrote on the condolence book.

Also attending the condolence ceremony were director of the Liaison Office of the Central People's Government in Hong Kong Peng Qinghua, Commissioner of the Ministry of Foreign Affairs Lu Xinhua, and Vice Political Commissar of the PLA Garrison Troops Rao Xinjian.

Other principal officials of the Hong Kong government also sent condolences and regards to the victims and their families.

The 18 condolence points will be open until Thursday.

Also in the day, Convenor of the Non-official Members of Hong Kong's Executive Council, Leung Chun-ying, issued a statement, in which he said they were "deeply saddened and outraged at the hostage incident".

"We mourn for the Hong Kong people who died in the incident and extend our condolences to their family members. We also wish those who were traumatized and injured a speedy recovery.

"We condemn the atrocity committed by the culprit, which caused deaths and casualties among innocent Hong Kong people," said Leung.

"We strongly urge the Philippine government to give an account of the incident openly, explain the ways the incident was handled, assist fully the Hong Kong government to deal with the aftermath as soon as possible, and ensure the safety of all of the Hong Kong people in the Philippines," said Leung.

Hong Kong plunged into deep sadness, as all the city's government offices lowered flags at half-mast to mourn the hostage victims on Tuesday.

The city government said that the Hong Kong Special Administrative Region flags at all government offices would continue to be flown at half-mast on Wednesday and Thursday as a token of mourning for victims of the hostage incident.

Also in the day, major newspapers in the city were printed in black and white to pay tribute to those killed. Home pages of government websites were also turned black and white.

Local bourse operator Hong Kong Exchanges Clearing Ltd held a one-minute memorial ceremony in the morning before the stock market opened.

Monday's 11-hour hostage crisis in Manila, which was broadcast live on TV, had shocked the city's 7 million residents, with a few of them turning to psychological support.

A hotline operated by Hong Kong Red Cross and the Division of Clinical Psychology of the Hong Kong Psychological Society had received 100 calls for psychological assistance who were disturbed by the hostage crisis, said Hong Kong Red Cross.

The organization said its hotline had received a total of 100 calls for psychological assistance as of 8:00 p.m. local time on Tuesday, of which nearly 80 percent of the cases need counseling by clinical psychologists.

Among the calls, the youngest inquirer was only 8 years old, it said.

The majority of the calls received were people who felt emotionally disturbed or in psychological discomfort due to the hostages incident, while some of them were even worried about encountering similar incidents when going abroad in future, said the Red Cross.

Lau Yu Po-kwan, Clinical Psychologist and Professional Advisor of the Psychological Support Hotline Service Team, said the city's residents needed to pay more attention to their daily lives such as diet, sleep and work, etc.

The hostage crisis in Manila, involving a 21-member Hong Kong tour group, ended on Monday night with eight hostages dead and several others injured, one of whom in critical conditions.

The 21 Hong Kong tourists along with four Filipinos including a driver and a guide aboard a bus were taken hostage by a dismissed Filipino policeman on Monday morning.

The hijacker was killed by police in a rescue operation after he shot dead several hostages.