Nigerian Boko Haram militants have carried out an attack on Chad overnight, the first such assault on Chadian soil, officials say.
Fighters crossed Lake Chad in four motorboats and attacked a village, an army spokesman told the BBC.
The Islamist militants were pushed back by Chadian troops after killing several people, residents said.
Chad recently joined Nigeria, Niger, and Cameroon in a military coalition against Boko Haram.
The jihadists, who want to create their own Islamic caliphate in Nigeria, have killed thousands and forced millions to flee their homes in north-eastern Nigeria since 2009.
Colonel Azem Bermandoua Agouna, of the Chadian military, told the BBC’s Thomas Fessy that the militants had killed one soldier and wounded a further four in the village of Ngouboua.
Mr Agouna said a local chief was killed during the attack by a stray bullet. He did not confirm reports of other civilian casualties.
Two Boko Haram militants were killed and five injured, he said.
Residents put the number of attackers at around 30 and said they torched two-thirds of the village’s homes.
“They came on board three canoes and succeeded in killing about 10 people before being pushed back by the army,” one resident told Reuters.
Chadian military aircraft carried out air strikes against the militants in response, destroying their vessels, officials said.
Refugees from Nigeria arrive by boat in the Chadian village of NgoubouaThousands of refugees from Nigeria have fled by boat to the Chadian village of Ngouboua
Chad formed a military alliance in January with Nigeria, Niger, and Cameroon, aimed at defeating Boko Haram.
Chad, seen as having the region’s most effective military, has conducted airstrikes against the jihadist group in both Nigeria and Niger, and stationed its troops in the border areas around Lake Chad.
The Islamist militant group has intensified its attacks against Nigeria’s neighbours in response, forcing thousands of residents to flee their homes.