National and regional flags at all government buildings in Hong Kong will be flown at half-mast for three days starting on Thursday to pay last respects to the victims of a fatal ferry crash, the city government said in a statement Wednesday.

At midday on Thursday, a ceremony led by Hong Kong Chief Executive CY Leung and other principal officials will be held in front of the city government's headquarters to observe three minutes of silence in mourning.

Except for emergency and immigration services, other government services will be suspended during the period. All staff on duty will observe the three-minute silence at their work places.

Thirty-eight people including at least five children were killed after two ferries collided on Monday evening off Hong Kong' s Lamma Island. As at 4:00 p.m. local time on Wednesday, 22 injured people remained in hospital, two of them were in critical or serious conditions.