An army tank has shelled a funeral tent erected by the Southern Movement at a school in Yemen, killing 13 people, including three children, medics and officials said.
A security official told the Associated Press news agency the shells landed on Friday in the city of Daleh as mourners were paying condolences to the family of a man killed in clashes between security forces and gunmen affiliated with the Southern Movement, which is campaigning for autonomy or outright secession for the south.
The official and local political leader Adnan Abdo, who said he was at the site of the attack, said four shells hit.
"Thirteen people have died, among them three children," a medic from al-Nasr hospital in Daleh, 300km south of the capital Sanaa, told the AFP news agency. Medics at other hospitals said more than 20 people were wounded, some critically.
The deaths may inflame regional sentiment in southern Yemen, where a strong movement already demands greater autonomy from the north after what it describes as two decades of marginalisation and discrimination. South Yemen was an independent state until unification in 1990.
A local army officer, who asked not to be named, told Reuters news agency that a military outpost had fired the shell by mistake, and the man in charge was being investigated.
President Abd-Rabbu Mansour Hadi set up a committee to investigate the incident, state news agency SABA reported, without going into further details.
The slain man had been killed in clashes in Daleh erupting on Monday when secessionists attempted to storm the governorate building to hoist the flag of the former South Yemen.
Violence has intensified in south Yemen amid anger over the killing of local tribal chief Said Ben Habrish and his bodyguards at an army checkpoint earlier this month after they refused to hand over their weapons.
A long-running dispute over whether and how to grant the south limited autonomy has hindered the political transition following the 33-year rule of Ali Abdullah Saleh, who stepped down last year following Arab Spring-inspired protests.