A Canadian border guard remains in stable condition after a gunman shot her in the neck and then turned the gun on himself at the busy Peace Arch Crossing between British Columbia and Washington State, several news reports said.

The shooting occurred about 2 p.m. on Tuesday at the crossing, which is about 45 kilometres (27 miles) south of Vancouver, according to Canadian news outlet Cnews.

“In the instant following the shooting of the officer, the lone male had been pronounced dead at the scene from what appears to be a self-inflicted gunshot wound,”' Cpl. Bert Paquet told reporters.

While Paquet didn’t give details on the female guard’s name or age, the identity of the gunman is also yet to be released.

As authorities continue their investigation into the incident, Paquet told reporters that the suspect “was entering Canada in a vehicle that (had) a Washington plate.”

Police are trying to determine what prompted the attack.

“We are working right now with all available resources at the scene to try and establish exactly the sequence of events that took place between the arrival of this individual to the Peach Arch Crossing and, subsequently, what led to the events that unfolded,” Paquet said.

An eyewitness, who was waiting in line at the border crossing, told reporters he saw armed border guards surround a white van, Cnews reported.

“I saw all the border guards running to that white van, yelling and screaming, ‘Get out of the van,' and guns drawn,” the witness said.

Public Safety Minister Vic Toews said he was deeply concerned by the shooting.

“My thoughts and prayers go out to the family and colleagues of this border service officer,” Toews said in a statement.

“This event is a sobering reminder of the dangerous conditions faced daily by the men and women of our law-enforcement agencies as they work to protect the safety and security of Canadians.”