N'DJAMENA - Chadian President Idriss Deby sacked his defence minister on Saturday following a week of clashes between government troops and rebels in the east of the landlocked African country.

A presidential decree said Mahamat Nour Abdelkerim, a former anti-Deby rebel chief who became defence minister in March after signing a peace deal with the government, had been dismissed.

Official sources said Nour had taken refuge in the Libyan embassy in N'Djamena.

No reason was given for the sacking, but Nour's position had been tenuous since last month, when former rebel fighters loyal to him were involved in ethnic clashes with a rival community on Chad's eastern border with Sudan's violent Darfur region.

The former members of the rebel United Front for Democratic Change (FUC) which Nour once led come from the Tama ethnic group and they had been resisting efforts to disarm them by the government army and militia from Deby's own Zaghawa ethnic clan.

Chadian troops and ex-FUC fighters clashed on Friday at Guereda, an eastern border town in the Tama heartland.

Deby's sacking of his defence minister injected further uncertainty into the situation in conflict-torn eastern Chad ahead of the planned deployment there of a European Union peacekeeping force early next year. The EU force has been tasked by the United Nations to protect refugees and aid workers.

No replacement for Nour was immediately announced.

Deby himself had been directing combat operations by the government army this week against rebels of another rebel group, the Union of Forces for Democracy and Development (UFDD), which abandoned a month-old peace accord a week ago.

In the worst fighting in eastern Chad in months, government troops and the UFDD rebels fought several battles which both sides said killed hundreds. The UFDD is led by another former defence minister, Mahamat Nouri, who defected to join a two-year-old eastern insurgency against Deby.

Diplomats said Nour's sacking could trigger more bloodletting around Guereda between Nour's Tama fighters and members of Deby's ruling Zaghawa clan.

Chad declared a state of emergency last month along its eastern border with Sudan's Darfur after ethnic fighting between the Tamas and Zaghawas killed at least 20 people.

Deby's government has accused Sudan of supporting the UFDD rebels, who are largely drawn from their chief Nouri's Gorane ethnic group. Khartoum routinely denies accusations that it supports anti-Deby rebels.