CANBERRA -- Police have apprehended a 43-year-old man alleged to have intentionally rammed a member of Australia's Federal Parliament with a four-wheel drive vehicle on Monday, leaving her in critical condition.

Helen Haines, an independent elected in 2019, was struck outside her electorate office in the town of Wangaratta in the southeastern state of Victoria, in what Prime Minister Anthony Albanese described as a "deliberate act," which happened as Haines was retrieving belongings from the boot of her car.

"Now, the motivation is not clear at this point in time, but it is clear that this wasn't just an accident," Albanese told television outlet Channel 7 on Tuesday. "This was an attempt to harm Helen Haines in Wangaratta outside of her electorate office."

Australian Federal Police Commissioner Krissy Barrett issued a statement, saying, "At this stage it appears this is an isolated incident, and there are no known threats connected to this matter." The attack follows warnings by the AFP and the Australian Security Intelligence Organisation (ASIO) about growing threats against federal parliamentarians and other holders of political office as polarization increases in the nation of 28 million.

Victoria police have yet to disclose information about the suspect's possible motive. In a statement, police said Haines was struck with a Toyota Land Cruiser at about 3:35 pm. Police said they seized a knife from inside the vehicle.

"When he exited the Toyota the driver, a 43-year-old Tarrawingee man, was arrested at the scene by a passerby," Victoria police said. "He will be interviewed in relation to the incident." Haines, 65, was airlifted to a Melbourne hospital, where she underwent surgery. The ABC, the national broadcaster, reported on Tuesday that she had required the amputation of a leg and remained in critical condition.

Albanese said last night that the Joint Counter-Terrorism Team had been activated and the AFP was also investigating. Australia's Minister of Home Affairs Tony Burke told journalists that bystanders had intervened after the attacker struck Haines twice.

"What witnesses have described is the driver doing a U-turn to get into the car park and to ram Helen against her vehicle. Then to reverse and do it a second time," Burke said.

"A bystander ran towards the scene, got the driver out of the vehicle and held the driver until police arrived," he said.

Independent member of parliament Helen Haines speaks to journalists in the Press Gallery at Parliament House in Canberra, Australia, on Sept. 8.

Australia's political landscape has been shifting as the once-fringe right-wing One Nation Party has seen its support grow on the back of frustration about the cost of living and migration. Questions over social cohesion have spiked, particularly following a deadly terrorist attack against a Jewish community gathering last December.

One Nation leader Pauline Hanson released a statement on Monday saying, "Violence against any elected representative, whoever they are and whatever they stand for, is never acceptable in Australia."

Albanese said that political discourse was going in the "wrong direction" and "called for the temperature to be turned down." The AFP said there were 1,067 reports of harassment, nuisance, offensive and threatening behavior against high office holders and elected representatives this year as of June 30, a 12% increase over the previous year.

Mike Burgess, head of ASIO had previously warned about an increased risk of politically motivated violence as polarization, frustration and anti-authority beliefs grew and trust in institutions eroded.

"While political differences, debates and peaceful protests are essential parts of a healthy democracy, ASIO has seen direct correlations between inflamed language, inflamed tensions and acts of violence," he said in a statement on Tuesday.