One of the pair, Nguyen Van Tinh, was among a group of six jailed in the northeastern port city of Hai Phong in October 2009 for hanging democracy banners and committing other acts against the state.

Tinh, who was born in 1942, had been sentenced to three and a half years in jail.

A total of 10,244 serving prisoners were granted amnesty under a presidential order that took effect last Thursday, officials said at a news conference.

These included people arrested for a range of crimes, including murder, drug trafficking, trafficking women, and bribery.

The amnesty is an annual event to mark the country's September 2 National Day. Last year more than 17,000 inmate were pardoned and about 5,000 were freed in 2009.

"This once again demonstrates the clemency policy of the Party and State and the humane traditions of the Vietnamese people", Giang Son, vice-chair of the president's office, told reporters.

The other activist freed under this year's amnesty was poet Tran Duc Thach, who was also jailed in October 2009.

A friend said at the time that he was jailed for three years on a charge under Article 88 of the Penal Code, which rights activists say criminalises peaceful dissent.

According to the US-based Human Rights Watch, Thach's writings "condemn corruption, injustice, and human rights abuses". The watchdog said last year that Thach, who is in his late 50s, had been arrested 10 times since 1978.

Tinh and Thach, who were convicted for "propaganda against the state", were two of five people convicted of "national security crimes" who were released.

Of the other three, one was convicted of a "security disturbance" and two were convicted of "disturbing national unity".

Deputy minister of Public Security, Lieutenant general Le Quy Vuong, could not give a figure for the number of Vietnamese in prison for national security crimes but he said the total number of inmates was more than 100,000.

In April, rights group Amnesty International voiced concerns about the continuing detention of dozens of political critics and activists jailed since late 2009.

The release of Tinh and Thach follows international criticism of Hanoi over other recent rights cases.

These include: the three-year sentence given to French-Vietnamese lecturer and blogger Pham Minh Hoang this month; an appeal court's confirmation, also this month, of a seven-year jail term for prominent dissident Cu Huy Ha Vu; and the re-incarceration in July of a Catholic priest, Nguyen Van Ly, who has a brain tumour.

Agence France Presse - August 30, 2011