Yemeni and Emirati troops plunged into the southern port city of Mukalla on Sunday, said residents, entering a stronghold of the Yemeni wing of Al Qaeda militant group for the first time in over a year of war.
"Coalition armoured vehicles and the army entered Mukalla and Al Qaeda fighters [militants] are departing," said one resident, who declined to be named for security reasons.
Warplanes pounded the Al Qaeda-held port city of Mukalla on Sunday and killed 30 militants, residents said, as a Gulf Arab military coalition ramped up an offensive to wrest swathes of southern Yemen from the militants' grip.
In the past year, Al Qaeda gradually took control of an almost 600-km (370-mile) band of the Arabian Sea coastline and built a so-called mini-state centred in Mukalla, sustained largely by customs revenue from the port.
Sunday's air strikes on Al Qaeda were carried out in coordination with a ground offensive in the militant-controlled territory further west, a Yemeni military official said.
The push is being led by the United Arab Emirates, which has been training and arming local recruits for months, according to southern Yemeni tribal and political sources.
"The liberation of Mukalla from the hands of the Al Qaeda terrorist organisation [militant group] has begun," governor Ahmed Saeed Bin Breik said in a statement.
Local officials said dozens of armoured vehicles and hundreds of troops are gathered in Ramah, around 70 km (44 miles) north of Mukalla in preparation for a ground push.
The UAE is part of a mostly Gulf Arab coalition which intervened in Yemen's civil war in March last year to support the internationally recognised government.
Sunday's air strikes come as the Yemen's government meets with the Houthis in Kuwait to try to find a solution to the conflict
Around 6,200 people have died in the war, which has focused mostly around the country's Houthi-controlled centre and north, while a security vacuum spread in the south.
The United States has used drone strikes for years in Yemen to target Al Qaeda in the Arabian Peninsula, the group's local wing, which had plotted to place bombs on international airliners and claimed credit for the Charlie Hebdo magazine attack last year.
Winning back territory
Fearing more air strikes, residents reported that local families were bundling into cars and driving out of town.
On Saturday, Yemeni troops battled Al Qaeda at al Koud near Zinjibar, another southern city considered an Al Qaeda stronghold, while an air strike from a drone killed two suspected Al Qaeda militants south of the city of Marib.
In a statement on its official Twitter account, Al Qaeda in the Arabian Peninsula said it carried out a suicide bombing attack against the government troops pushing into al Koud.
The Houthis control the capital Sanaa in the north while the Saudi-backed Yemeni government has tried to re-establish itself in the southern port city of Aden. Only in the last month has its fledgling army begun to make gains against the militants and organise to take back lost territory.