Yemeni government forces entered the port city of Aden Wednesday and recaptured the city's international airport during clashes with separatists, officials said.
The government troops earlier Wednesday pushed United Arab Emirates-backed militia out of Zinjibar, the capital of the southern Abyan province, after the separatists seized the city earlier this month.
Yemeni Information Minister Moammer al-Eryani tweeted that the "Heroes of the national army and security agencies have retaken Zinjibar city ... and complete their control over the other districts of the province."
The latest clashes deepen the rift between presumed allies in a Saudi-led coalition. The separatists, known as the Security Belt, are nominally united under the coalition in the fight against Yemen's Iran-backed Houthi movement.
Officials said the separatists fled Zinjibar for the neighboring Aden province, which they captured earlier this month from the forces of Yemeni President Abed Rabbo Mansour Hadi.
Just weeks earlier, the separatists had pushed government forces out of strategic cities and areas in southern Yemen.
Clashes between the two sides highlight the complexity of the civil war in the Arab world's poorest country.
Aden has functioned as the seat of President Hadi's government since the Houthi rebels captured Yemen's capital of Sanaa and much of the country's north in 2014.
After Wednesday's seizure of Aden, Hadi's supporters were seen in online videos dancing in the streets of the port city and Zinjibar.
The coalition invited the two sides to Saudi Arabia days ago to negotiate a cease-fire it has called for, but Hadi's government said it would not negotiate before the separatists withdraw from all key government facilities in the south.