Siege underway in Canberra

Police say they have established telephone contact with a man who has barricaded
himself inside a house in Canberra's south.
A number of streets around the suburb of Holder have been cordoned off and residents
have been evacuated.
The siege began at about 11am (AEST) but circumstances surrounding the cause of the
incident remain unclear.
Police said they were concerned about threats involving explosive materials made by
the elderly man but have ruled out a bomb.
More than 30 police officers have descended on the area and HAZMAT team is also on
the scene.
Negotiations with the man are continuing, ACT Police said.
It is understood the man is alone in the house.
A number of unaccompanied children are now in the care of authorities due to the
threat in the area.
Police have established a 700 metre exclusion zone around the area.
Evacuated residents are being accommodated at a school in the nearby suburb of Phillip.
"Around 11am today police were called to attend a residence on Dixon Drive, Holder
where a man has barricaded himself inside a house," police said in a statement.
"All unaccompanied children are being cared for by police and emergency services
until their parents or guardians are able to pick them up."