Police have evacuated a block of units in Red Hill after a man barricaded himself inside an apartment on Sunday.
Police said they ordered the evacuation after noticing a "strong smell of fuel coming from the apartment".
Police have closed Monaro Crescent south of La Perouse Street.
ACT Policing said officers were negotiating the surrender of a 39-year-old man in the block on Monaro Crescent. They are addressing him through a loud speaker.
They said they were alerted to the incident by the person who lives in the unit earlier on Sunday. The resident told police that the 39-year-old man had barricaded himself in the unit overnight after an argument, and that he had allegedly assaulted the resident with a weapon.
"While the offender was distracted, the man managed to flee the apartment and went to City Police Station around 10am. He alerted them to the location of the offender who is still in the unit," police said.
Officers have established a cordon around the unit and have attempted a negotiated surrender."
One neighbour from the block of units, who did not want to be named, said he noticed a smell of petrol around the building in the afternoon.
"I thought what the hell is that?" he said.
"I just didn't think twice about it."
Another neighbour, who also didn't want to be identified, heard commotion outside at 4am on Sunday.
"There was a car dropping somebody off," she said.
"There was a lot of noise happening. I thought maybe my laundry was being broken into."
When she went outside she saw the noise came from the unit the man has barricaded himself in.
Police have taped off pathways near the units and the Red Hill shops and were continuing negotiations as of 8.20pm.
Police arrived at the scene about 3.30pm, and ordered the evacuation a short time later.
Police's Specialist Response Group of negotiators, tactical response unit and canine unit are on scene, as are firefighters and ambulance intensive care paramedics.
