Infighting among pro-government Yemeni forces has killed 35 troops in a southern province in the past 24 hours, officials said, a development that threatens a ceasefire in the country's wider conflict.
They say that an artillery duel that starts in the late hours of Tuesday hit areas around a local airport in the city of Ataq, the capital of the southern Shabwa province.
Five civilians were among the dead, they added, speaking on condition of anonymity because they were not authorized to brief the media.
The fighting comes after months of tensions within the pro-government, Saudi-led coalition that has been fighting a common enemy — the Houthi rebels — since 2015.
Earlier violence late on Sunday erupted in the area after the province's governor, backed by the United Arab Emirates, decided to sack a police commander known to have an anti-UAE stance, the officials said.
Yemen's civil war erupted in 2014 when the Iran-backed Houthis descended from their northern enclave and took over the capital, forcing the government to flee to the south before its exile in Saudi Arabia.
A Saudi-led coalition — then backed by the US — entered the war in early 2015 to try to restore the government to power.
Since then, the conflict has turned into a proxy war between regional foes Saudi Arabia and Iran, which backs the Houthis. The war has also resulted in one of the world's worst humanitarian crises.
Last week, the rebels and the government agreed to renew an existing truce, in place since April, for two more months after concerted international efforts.
(Inputs from PTI)