Queanbeyan stabbing: Counter-terrorism police investigate fatal rampage

NSW Police say physical evidence found at the scene of a fatal stabbing at a Queanbeyan petrol station suggests the attack was terror-related.

Two teenage boys were arrested this morning after allegedly going on a rampage that left one man dead and another seriously injured.

The pair were taken to a watch house in Canberra but police planned to seek their extradition back to NSW today.

The 15 and 16-year-olds allegedly stabbed a service station attendant to death at Queanbeyan about midnight before taking off with the station's cash register and several other stolen items.

Deputy NSW Police Commissioner Catherine Burn said the investigation now involves NSW Police, the Australian Federal Police, ASIO and the Crime Commission.

Ms Burn said the high-level response meant police could use all of the resources from all agencies to investigate the potential terror link.

PHOTO NSW Deputy Commissioner Catherine Burn described the attack as brutal.

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She also reassured the public that there was "no imminent attack".

Ms Burn said police believe only one of the boys, the 16-year-old, was linked to terrorism, but both are known to police.

She said the information was only received within the past few hours through sources and other information.

Earlier today Monaro police commander Superintendent Rod Smith said it appeared the pair, from Queanbeyan, had also been involved in a series of "absolutely horrific" attacks nearby overnight.

That allegedly included stabbing another man in the abdomen. He was taken to Canberra Hospital in a serious but stable condition.

Police said another man was bashed with a tyre iron in an aggravated break and enter, while yet another was hit with a beer bottle in a nearby park.

The pair was also allegedly involved in another attempted robbery at Oaks Estate in the ACT.

"It doesn't need to be said but it doesn't get much more serious than this," Superintendent Smith said.

"We'd just like to reassure everybody that there are two people that we believe are involved and both of those people are currently in custody."

Prime Minister Malcolm Turnbull spoke at Parliament House earlier today and said the circumstances raised "sufficient concern" to warrant the involvement of the joint counter-terrorism team.

Mr Turnbull said the crime "is shocking and a matter which underlines many of the concerns we have raised in this field".

Police chased teens across state border

PHOTO The service station building was also damaged.

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Emergency services were first alerted to the service station stabbing by an employee when he arrived at work about midnight to find his co-worker suffering serious stab wounds.

The 29-year-old man died at the scene and Superintendent Smith said his co-worker was "obviously very shaken".

The offenders had become locked inside the store and allegedly smashed their way out a window to escape.

Superintendent Smith said the two teenagers had been arrested following a police chase about 6:30am.

A weapon was found in that car but Superintendent Smith said it was not clear whether it had been used in the attacks.

The teenagers are yet to be charged.