A Hanoi court on Wednesday ordered the jailing of two activists who posted on Facebook about a land dispute clash that left four people dead on the outskirts of Vietnam's capital last year.

Vietnam's government takes a zero-tolerance approach to criticism on social media.

Trinh Ba Phuong was sentenced to 10 years and Nguyen Thi Tam to six years for "making, storing, distributing or propagating information and documents aimed at opposing the Socialist Republic of Vietnam".

Three police officers and a resident were killed during a clash at Dong Tam commune in January 2020 after officials attempted to erect a fence and were met by villagers armed with "grenades, petrol bombs and knives".

Villagers had been resisting the military's attempts to build an airport on their land.

Phuong and Tam's content "distorted and fabricated the situation taking place in Dong Tam commune, defamed the people's government, incited people to oppose the authorities", according to state-controlled Vietnam News Agency.

Phuong's mother and younger brother were sentenced to eight years in jail in May, also for posting online about the incident.

Their court appeal is scheduled for this month.

In September last year, a Hanoi court sentenced two men to death for the murder of the three police officers -- and 27 others were convicted over the incident.

Land disputes are common in Vietnam, where powerful individuals and companies often make property claims.

Phuong and Tam's sentencing comes a day after a prominent dissident journalist was jailed for nine years.

The United States and British governments condemned the conviction of Pham Doan Trang -- a campaigner for press freedom and civil rights -- and called for her release.

"The United States calls on the Vietnamese government to release Trang... and to allow all individuals in Vietnam to express their views freely and without fear of retaliation," US State Department spokesman Ned Price said.