HONG KONG - Nine people were killed and more than 30 others were injured in a fire that lasted over seven hours in downtown Hong Kong on Wednesday.

The Hong Kong Special Administrative Region government's Criminal Investigation Department has been involved in the case as arson was suspected.

According to the latest press release by the government, 33 people were injured in the incident while the number reported by the local media was 34, six of which were in critical situation.

The blaze started at around 04:40 am local time at hawker stalls on Fa Yuen Street (also known as the Sneaker Street) in Mong Kok on Kowloon Peninsula, and then spread to the neighborhood. It was not finished until 12:28 pm local time. The fire was largely put out by 12 jets and 12 breathing apparatus teams.

The cause of the fire is still unknown, but the possibility of arson can not be ruled out, said a spokeswoman from the Mong Kok police department.

The government will try every effort to investigate the incident, she said.

In December last year, a similar fire broke out close to the scene, causing several people injured and many hawker stalls burned to the ground.

Chief Executive Donald Tsang spoke to reporters after visiting the injured, including a one-year-old child, at Kwong Wah Hospital. He said that fire-safety measures to prevent such a tragedy from reoccurring were inadequate.

They included separating hawker stalls, reducing illegal extensions and ensuring stalls were set apart from buildings.

"This is a serious tragedy," he said, adding "we are sparing no resources. Every resource is put into place - manpower, money - to make sure victims are looked after, and at the same time we deal with their needs, housing, immediate financial needs, et cetera."

The Home Affairs Department and Social Welfare Department have set up help desks to look after the needs of victims and affected residents, including housing and immediate financial assistance.

As of 05:00 pm local time, 359 affected households had registered with the inter-departmental help desks.

Huge economic losses were feared for shops at the site as they are stocking up for the upcoming holiday season. More than 20 stalls may be affected, among which 12 were burned out, reported the local media quoting the chairman of a local sellers guild.

Mong Kok is one of the most densely populated areas in Hong Kong known to tourists for its traditional markets and small shops.