HANOI (AFP) -- Bomb has exploded in the Lao capital Vientiane in the latest in a series of attacks aimed at destabilizing the communist regime, diplomats said Saturday.

The blast took place Friday evening near the Patouxay monument in central Vientiane, but no one was killed or injured, a Western diplomat said, confirming a report by the U.S. government-funded Radio Free Asia (RFA).

The monument, which is known as Vientiane's Arc de Triomphe, is located near the city's main boulevards and government offices.

Laos has been rocked by a series of attacks this year, which observers say could have been carried out by small, rag-tag bands of ethnic minority rebels opposed to the communist regime.

The guerrillas, mainly from the Hmong minority, have waged an ineffective, low-level insurgency for nearly three decades since being abandoned by their U.S. sponsors at the end of the Vietnam War.

The Lao military has been accused by human rights groups of using heavy-handed and often brutal tactics to eliminate them once and for all.

Friday's blast follows an October 19 grenade attack in the capital and an explosion at a market in the southern province of Savannakhet on the same day, in which two people were killed and at least five others injured.

At least 10 people were also injured in an explosion on August 4 at a bus station in Vientiane.

The capital was gripped by a series of 14 bombings between 2000 and 2001 in which four people were killed and more than 40 injured.

No one, however, claimed responsibility for this bombing campaign until earlier this week when a group calling itself the Free Democratic Peoples Government of Laos said it was behind them.

"The Lao government should stop blaming outsiders for these bombings. We are responsible," the group said in a statement faxed Monday to RFA's Bangkok office.

"We are in Laos ... Why did you bring Vietnamese troops and station them with the Lao military all over the country?" the statement said, referring to thousands of Vietnamese troops reportedly stationed in Laos since the 1970s. "Is it to help you massacre citizens who may take up arms to fight you?"

Vietnam maintained an official military presence in Laos until 1989 and continues to exert considerable influence over its fellow communist neighbor. Hanoi, however, has repeatedly denied that its troops are still active there.

Two Laotians were jailed for life in September for the 2000-2001 bomb attacks and the government subsequently said it believed they were planned outside Laos.

This followed claims in July by a U.S.-based Lao advocacy group, the Fact Finding Commission (FFC), that "pro-democracy" forces, who included ethnic minority rebels and other dissatisfied elements, had begun an uprising to topple the government.

Meanwhile, the FFC, citing prison sources, said Friday that two detained Hmong men -- Thao Moua and Pa Fue -- have been "brutally tortured" by Lao authorities.

The pair were arrested and jailed in June while helping two European journalists and an American pastor report on the plight of the Hmong rebels. The three Westerners were released in July.

The Lao government could not be immediately contacted for comment.