People across Hong Kong have observed three minutes' silence for the eight tourists killed in a bus hijack in the Philippines on Monday.
Chief Executive Donald Tsang led a sombre mourning service on Hong Kong's waterfront as flags flew at half mast.
Emotions are running high in Hong Kong after coffins bearing the victims of the siege arrived home.
Philippine police have admitted to poor handling of the siege and several officers have been removed from duty.
But Hong Kong residents remain angry at what they see as the incompetence of the Philippine authorities.
"There's no way that we can participate in the investigation of the event," Hong Kong's Secretary for Security Ambrose Lee said, ahead of a debate by Hong Kong legislators later on Thursday.
"But we will urge the Philippine authorities to conduct a thorough, just and transparent investigation and we want the report to be ready as soon as possible."
Hong Kong people have criticised the Philippines police for failing to respond quickly or effectively enough after the bus was hijacked by an armed former police officer who wanted his job back.
In scores of blogs, protest letters and talk shows they have puzzled over how a tour could have gone so badly wrong
Some comments have become inflammatory, attacking any Filipinos, but the overall mood is grief; many of Hong Kong's 200,000 Filipino residents have also attended mourning services.
Thursday's service followed a ceremony held at Hong Kong's International Airport when the bodies were returned.
The BBC's Hong Kong correspondent Annemarie Evans said relatives of those who died were overcome.
As bagpipes played, the mother of one of the victims, Hong Kong tour guide Masa Tse, laid a wreath and then hugged his coffin.
Mr Tse, who was 31 years old and wanted to be a yoga teacher, had made a quick call to his tour agency Hong Thai Travel on his mobile phone from the back of the hijacked tour bus on Monday.
He was then used as a human shield by the hijacker at the front door of the bus and was later shot dead.
On Wednesday, a spokesman for the Philippine police said that four officers who led the assault on the bus had been suspended pending an investigation.
Manila police chief Rodolfo Magtibay has also said he will take a leave of absence.