CS gas fired into siege flat
It followed an earlier exchange of fire between gunman Eli Hall and armed officers.
Part of the building in Hackney, east London, was already on fire and police fired the CS rounds into an area away from the blaze where they believe Hall, 32, is hiding. Officers resorted to CS rounds to try to force him out in what has become one of Britain's longest armed sieges.
Hall had earlier set light to the bedsit and palls of smoke continued to rise as emergency service workers battled to get the fire under control.
Before that he had fired three shots at police from the second floor of the building at about 9.15am.
Armed officers from the Metropolitan Police fired one shot in response.
They then shot baton rounds through windows to allow them to tackle the fire.
The development comes as the siege entered its 15th day, making it one of the longest in English history.
Commander Bob Quick, who is leading the operation, said: "Armed police officers, at some personal risk, used fire brigade equipment to extinguish the fire. The suspect is still moving around in the premises but we have no further update on his physical condition.
"There appears to be a substantial fire with smoke billowing out of most of the building."
The officer said Hall was likely to have inhaled a "considerable amount" of smoke but conceded that he could have survived the fire.
Commander Quick revealed on Wednesday that negotiations with the gunman had taken a step backwards and that he had adopted a "very entrenched" position.
Officers had previously believed that negotiations were proving effective, raising hopes it could be resolved peacefully.
But negotiations broke down on Wednesday night and there was no contact until the shots were fired.
Hall is believed to have handguns and a cache of ammunition inside.




