Yemeni separatists have taken effective control of the port city of Aden after days of fighting with troops loyal to the internationally backed government.
Forces aligned with the UAE-backed Southern Transitional Council (STC) - which wants an independent south - said they had seized control of military camps and the presidential palace, reports BBC.
The opposing Saudi-led coalition said it had responded with military action.
The government itself characterised the STC’s seizure of Aden as a “coup”.
Coalition forces had called on the STC to withdraw from their positions in Aden or face further action. It said it launched its strike against a “threat” to the country’s government.