Fire-fighters rush to put out a fire that raged through an office building in northwest China's Shaanxi province for hours on Saturday.

The fire left at least one security guard trapped and 16 others hospitalised.

The official Xinhua news agency reported the fire broke out in the 16-storey World Trade Plaza in Yan'an city.

About 50 people staying at a hotel on the top floors of the building were evacuated, with 16 of them treated in hospital for minor carbon monoxide poisoning, said Xinhua.

State television CCTV said the fire had been brought under control by noon.

Police sealed off the roads surrounding the building and relocated over 1,700 residents in the neighbourhood.

More than 460 fire-fighters and police were mobilised to tackle the blaze.

The cause of the fire is under investigation, it added.