Chad's president has ordered the military to retaliate against future attacks from Sudan following a drone attack that killed at least 17 people and injured several other people attending a funeral.

Wearing military uniform, President Idris Mahamat Déby convened an emergency security meeting on Wednesday evening, where he ordered the military to be on high alert. He also ordered a 'total closure' of the border with Sudan.

He described the attack targeting the border town of Tiné as 'outrageous and a blatant aggression' against Chad's territorial integrity.

He said that it had happened despite warnings to the two sides battling each other in Sudan and a previous closure of the border.

Last month, Chad closed its border with Sudan 'until further notice' to stop repeated incursions by Sudanese armed groups. It however allowed 'exceptional exemptions' on humanitarian grounds, with prior authorisation from relevant authorities.

Residents of Tiné said the victims of Wednesday's attack were mourners, with one quoted by the Reuters news agency as saying they had gathered at a house for a funeral ceremony that involved reading the Koran.

The attack drew condemnation from several quarters, including from the National Assembly and MPs from the ruling party.

'When the shark is no longer swimming, it is because it is dead,' stated a local reflecting on the brutal nature of the violence that has persisted, as observers worry about the implications of military retaliation.

The paramilitary Rapid Support Forces (RSF), suspected of orchestrating the attack, denies involvement and blames Sudan's army, while historical grievances continue to shape Sudan-Chad relations amidst an ongoing civil war that has resulted in over 13 million displaced individuals, as reported by the UN.