The rebels, estimated to number around 1,500, crossed into north-eastern Rwanda from neighbouring Uganda on Sunday. Yesterday they were within 45 miles of the capital, Kigali, the Belgian foreign ministry said.
A ministry spokeswoman said rebels were fighting government troops near the towns of Gatsibo and Gabiro, north of Kigali. 'It's not difficult for the rebels to move to there. It's all savannah,' she said.
The Rwandan government sent reinforcements to the area yesterday, and the Rwandan Interior Minister, Jean-Marie Vianney, said the army was engaged in heavy fighting about 90 miles from Kigali. A dusk to dawn curfew was imposed on Tuesday.
Belgium has not yet replied to the appeal for help, and unconfirmed reports from Kigali said a similar request had been made to France.
The rebels, most of whom are Rwandan refugees who had been serving in the Ugandan army, are being led by Major-General Fred Rwigyema, a former deputy commander of Uganda's National Resistance Army (NRA), and a deputy defence minister until last December. Gen Rwigyema is a member of Rwanda 's minority Tutsi tribe, which was ousted from power by the majority Hutu in 1959.
The Ugandan President, Yoweri Museveni, has told President Habyarimana that the attack took Uganda by surprise. 'We have been taken aback by the scale and rapidity of the desertions,' Mr Museveni told Uganda's New Vision newspaper. Both leaders have been attending the United Nations summit on children in New York, but are now returning home.
The Rwandan army is understood to have sent all its operational units 3,000-4,000 men to the north-east, amid fears that more rebels are gathering on the Ugandan side of the border.
The Ugandan government has been seriously embarrassed by the affair. Yesterday, an official statement said the border would be sealed and all returning NRA soldiers would be tried for desertion.
'If President Museveni succeeds in closing the border, the invasion force inside Rwanda , will die out,' said a Western diplomat in Kigali. 'It was counting on local support, and that appears not to have materialised.'
In the Ugandan capital, Kampala, a spokesman for the Rwandan Patriotic Front stressed that although his organisation contained many Tutsi refugees, the rebels were not invading Rwanda primarily on their behalf. The first objective was to overthrow the 'corrupt' government of President Habyarimana.
The United Nations High Commission for Refugees reported that there were 75,000 registered Rwandan refugees in south-western Uganda at the beginning of this year. Thousands more live in other neighbouring countries Tanzania, Burundi and Zaire.
Rwanda , Africa's most densely-populated country, has consistently said it cannot allow the return of large numbers of refugees, as the country would be unable to cope with such an influx.
