HANOI (AFP) - A Vietnamese border guard open fire and injured three people at his patrol station before killing himself on Saturday (June 15), state media reported in the communist country where gun violence is extremely rare.

Civilians are banned from owning guns in Vietnam, a one-party state where a vast police force and soldiers are among the few officials with access to weapons.

On Saturday, a border guard in southern Long An province near Cambodia opened fire at his post injuring two colleagues and a local resident, according to the official Vietnam News Agency.

The shooter holed himself up at the post in Binh Hiep commune before committing suicide, VNA said, identifying him as second lieutenant Ta Quang Dat.

"Dat had shown recent signs of psychological disorder and he just returned from treatment," VNA reported.

Some unverified media reports said one of the injured victims later died in hospital.

Roads were blocked around the crime scene and local residents were evacuated from the area.

A local official requesting anonymity told AFP earlier "authorities were working at the scene", without providing further details.

Dangerous crimes are uncommon in Vietnam, though in recent years a small number of high-profile incidents have chilled the country.

In 2016 a forest ranger shot and killed two provincial officials in northern Yen Bai province before turning the gun on himself.

And last year a pipe bomb tore through a police station in southern Ho Chi Minh City, which officials later said was a politically motivated crime carried out by "terrorists".

Vietnam's lengthy and porous land border - which abuts Cambodia, Laos and China - is manned by soldiers in patrol posts.

There are 450,000 active duty soldiers in Vietnam, along with a five million strong reserve force, according to the Defence Ministry.

Mental health care largely lags in Vietnam, where specialised treatment centres are rare and social taboos abound.