Chad army, rebels fight at eastern border town

N'DJAMENA, June 4 (Reuters) - Chadian rebel and government forces clashed on the border with Sudan at the weekend as the rebels briefly occupied part of a frontier town to help two army officers and their men desert, a rebel leader said on Sunday.

Chad's government said Tine on the frontier with Sudan was attacked by "mercenaries in the pay of Khartoum", the term it uses to describe rebels opposed to President Idriss Deby who has ruled the landlocked central African oil producer since 1990.

It said government forces repulsed the attack.

In a separate development, Deby sacked his eldest son Brahim as his adviser after the 27-year-old was arrested in a Paris discotheque for possessing an illegal firearm and drugs. He was given a six-month suspended sentence by a French court.

The fighting at Tine was the first major clash reported between Deby's forces and the rebels since the insurgents attacked the capital N'Djamena on April 13, three weeks before polls which re-elected the president for a third term.

"Two officers from the government forces were trying to join us and asked for help. We sent fighters to get these people out," Yaya Dillo Djerou of the Chadian rebel group SCUD told Reuters, speaking by satellite telephone.

He said rebel fighters occupied the Chadian side of Tine, which straddles the border with the Sudan, Saturday night and then withdrew on Sunday after capturing equipment and destroying some vehicles. He gave no details of casualties.

A government statement released in N'Djamena said a rebel column of 67 vehicles attacked Tine on Saturday.

"The defence and security forces defeated the horde of mercenaries," it said, without offering details.

Deby, whose rule is bolstered by the presence of a French military force stationed in Chad, has accused neighbour Sudan of backing efforts to topple him by several Chadian rebel groups operating largely from the east. Khartoum denies this charge.

The rebel groups including SCUD, which is made up mostly of army deserters, have announced a military alliance against Deby.

REBEL CHIEF DENIES "DEATH" REPORT

In its weekend statement, Chad's government said a prominent anti-Deby rebel leader, ex-army captain Mahamat Nour, whose FUC (United Front for Democratic Change) attacked N'Djamena in April, had died from a heart attack in Dubai on Friday.

But Nour gave an interview late on Saturday to France's RFI radio to deny the report of his death. He said his forces were ready to resume attacks against the government even during the current rainy season which makes many roads impassable.

"We're more or less everywhere, even a few kilometres (miles) from the capital," he said.

He said his group was willing to negotiate but accused Deby of rejecting calls for a national political dialogue. "So we're obliged to fight to make him leave by force," Nour said.

The arrest and conviction in Paris of Deby's eldest son was another personal blow to the Chadian president, who has seen his leadership weakened by a spate of army mutinies and desertions, including members of his own family and Zaghawa ethnic clan.

Two nephews, once also senior advisers, have abandoned him to join the rebel ranks and another nephew, the chief of Chad's armed forces, was killed in a clash with rebels this year.

A government statement read on national radio said the arrest and conviction of Brahim Deby was not the responsibility of Chad or his parents. "He's a grown up," it said. (Additional reporting by Opheera McDoom in Khartoum and Pascal Fletcher in Dakar)