Former Burundian President Jean-Baptiste Bagaza has been placed under house arrest.

Home Affairs Minister Salvator Ntihabose told journalists in Bujumbura that Mr Bagaza, who is a senator, had been holding secret meetings with his party - Parena.

He accused Mr Bagaza of attempting to lead an uprising against the transitional government, and of planning to assassinate top ministers.

Jean-Baptiste Bagaza is viewed as a Tutsi hardliner

Tutsi opposition groups, like Parena, have criticised the talks with armed Hutu rebels taking place in Dar es Salaam seeking an end to the nine-year war.

On Monday, members of Parena were reported to be attempting to discourage people from going to work by throwing grenades in the capital.

War

On Sunday, a demonstration by Parena at Mr Bagaza's home was broken up by the police, and a number of party members were arrested on Friday.

Mr Bagaza seized power and was president of Burundi for much of the 1970s and 1980s.

He returned from exile last year as part of the peace process.

He was protected by South African bodyguards, but these are now reported to have been withdrawn.

Burundi conflict

War began: 1993 200,000 killed Hutus: 85% Tutsis:14% Twa: 1% Tutsis have dominated since independence

Prosecutor General Gerard Ngendabanka said on state radio on Saturday: "Bagaza has called for a jihad, a holy war, in his secret meetings. He has also called on young Tutsis to go into the streets. He even sends them out to kill people."

Last November a new transitional government was inaugurated sharing power between moderate Hutus and Tutsis, under a peace plan brokered by former South African President Nelson Mandela.

Hutu rebels rejected the new government, saying they had not been consulted.

The ceasefire negotiations resume in Dar es Salaam on Monday, and are led on the government side by President Pierre Buyoya, who ousted Mr Bagaza in 1987.

Talks

A deadline of 6 November was given by regional leaders for a deal to be reached, but one of the two main rebel groups still fighting, Rwasa Agathon's National Liberation Front (FNL), pulled out last week.

Regional leaders have warned the FNL and the other rebel group, the Forces for the Defence of Democracy (FDD), that if they do not reach a ceasefire by then they will face possible sanctions.

Heavy fighting was reported in northern Burundi at the weekend, with the army claiming to have killed some 50 FDD rebels.

Meanwhile two soldiers were reported killed and 10 wounded in an attack by FNL rebels on an army strongpoint in Buterere, northwest of the capital.

Since the civil war began in 1993 at least 200,000 people, most of them civilians, have been killed, but many deaths go unreported.

Heavy shelling was also reported in Gitega, the country's second city.

Thousands of refugees have been fleeing the upsurge in fighting.