Yemen's President Hadi makes surprise visit to Aden
Hadi is expected to stay for a few days in the southern port city, which is still prey to frequent unrest 18 months after his loyalists drove out Iran-backed rebels with the support of a Saudi-led coalition.
It is the president's first visit to Aden in a year and comes two months after Prime Minister Ahmed bin Dagher and seven ministers set up base in the city.
The government had previously operated from exile since October 2015.
The capital Sanaa, like most of the north of the country, remains in the hands of the rebel and their allies.
Hadi's authority is largely confined to the south and areas along the Saudi border.
Even within the south, his loyalists have faced repeated attack by militants of both al-Qaeda and its rival, the Islamic State group.
Security chiefs in Aden have been a particular target.
Hadi's visit came as fierce fighting raged between pro-government forces and the rebels following the collapse of a US-backed ceasefire on Monday.
The rebels launched a renewed assault on the outskirts of the town of Midi, on the Red Sea coast near the Saudi border, killing six soldiers and wounding 14, a military official said.
Loyalist forces captured the town in January but it has since changed hands several times.
The rebels lost two fighters but succeeded in clearing loyalist forces from the road between Midi and Haradh, a town inland that has also changed hands several times in the past year, the official said.
Further east, government forces launched a cross-border incursion from the Saudi province of Najran, capturing the long-closed al-Baqaa customs post and killing 18 rebels, another military official said, and six loyalists