By Mahamat Ramadane
N'DJAMENA (Reuters) -Chad's veteran president, Idriss Deby, has won a sixth term, provisional election results showed on Monday, as the army said it had beaten back a column of insurgents advancing on the capital, N'Djamena.
The 68-year-old Deby, who came to power in a rebellion in 1990, took 79.3% of the vote in the April 11 election, which was boycotted by top opposition leaders.
He was expected to give a victory speech to supporters, but his campaign director, Mahamat Zen Bada, said he had instead gone to visit Chadian soldiers on the front lines.
"The candidate would have liked to have been here to celebrate ... but right now, he is alongside our valiant defence and security forces to fight the terrorists threatening our territory," Zen Bada told reporters.
The rebel group Front for Change and Concord in Chad (FACT), which is based across the northern frontier with Libya, attacked a border post on election day and then advanced hundreds of kilometres (miles) south.
But it suffered a setback over the weekend. Chad's military spokesman, Azem Bermendao Agouna, told Reuters that army troops killed more than 300 insurgents and captured 150 on Saturday in Kanem province, around 300 km (185 miles) from N'Djamena.
Five government soldiers were killed and 36 were injured, he said.
FACT said in a statement that an "error" on Saturday had "slowed by a little bit the victorious march ... to N'Djamena" but that the rebels had routed the army in battle on Sunday and Monday, killing, wounding and capturing hundreds of soldiers.
Reuters was not able to independently verify the tallies of casualties.
Chadian state television on Sunday showed images of a crowd of soldiers cheering next to what state television said were dozens of captured rebel fighters, who sat with their hands tied behind their backs.
The unrest has raised alarm bells among Western countries, which have seen Deby as an ally in the fight against Islamist extremist groups, including Boko Haram in the Lake Chad Basin and groups linked to al Qaeda and Islamic State in the Sahel.
Deby, who has long faced insurgencies in the north, is also dealing with mounting public discontent over his management of Chad's oil wealth and crackdowns on opponents.
The United States ordered all of its non-essential embassy staff to leave the country on Saturday. The British government had urged its citizens to leave the previous day.
(Reporting by Mahamat Ramadane; Writing by Cooper Inveen and Aaron Ross; Editing by Alistair Bell, Peter Cooney and Kim Coghill)