Yemeni government forces captured Aden airport from southern separatists, according to local sources on Wednesday.
Government forces pushed deep into the city as fighters aligned with the Southern Transitional Council (STC) retreated, the sources said.
The sources said government forces moved into the districts of Mualla and Tawahi in the center of the city.
The new developments comes hours after government forces seized control of the Abyan province from STC forces.
"Large forces from the army arrived in the city from Abyan and Shabwa provinces after liberating the two cities from the STC forces," a local source said.
Earlier this month, southern separatists captured all government buildings in Aden after clashes with government forces.
Yemen has remained wracked by violence since 2014, when Shia Houthi rebels overran much of the country, including capital Sanaa.
The conflict escalated the following year when Saudi Arabia and its Sunni-Arab allies launched a massive air campaign aimed at rolling back Houthi gains in Yemen and supporting the country's pro-Saudi government.
The ongoing violence has devastated Yemen's basic infrastructure, prompting the UN to describe the situation as "one of the worst humanitarian disasters of modern times".
