An elite Yemeni force backed by Saudi-led coalition air strikes killed 30 suspected Al-Qaeda fighters in the southeast of the country in a 24-hour operation that ended Wednesday, the army said.

The force raided an Al-Qaeda hideout west of the port city of Mukalla on Tuesday in a "very successful" operation that lasted 24 hours, it said in a statement.

It said that 30 suspected militants were killed and several others were captured, increasing a Tuesday death toll of six alleged jihadists.

Four Yemeni troops were also killed and 12 were wounded in the fighting, it added.

The jihadists were "planning to carry out terrorist attacks" in the country, already torn apart by a 19-month-long conflict between Iran-backed rebels and loyalist forces supported by the coalition, the army said.

Mukalla was the most populous Yemeni city under Al-Qaeda control until government troops and coalition special forces recaptured it in April, ending a year of jihadist rule.

But the jihadists regrouped in the surrounding mountains from where they have carried out a series of deadly revenge attacks.

A security official told AFP on Tuesday that troops launched a "preemptive operation" against the extremists, who continued to pose a threat to Mukalla.

In July, suicide bombings claimed by Al-Qaeda killed 11 people at two army checkpoints in the city.

The previous month, Al-Qaeda's jihadist rival, the Islamic State group, claimed a wave of suicide bombings that killed at least 42 people in Mukalla.

Coalition forces intervened in Yemen in support of President Abedrabbo Mansour Hadi's beleaguered government in March last year.

But until earlier this year, they focused their firepower on Shiite rebels and their allies who control the capital Sanaa and much of the north and west of the country.

The jihadists have exploited the conflict to consolidate their grip on parts of the south, where they have enforced their often brutal version of Islamic law.

Washington regards Al-Qaeda's Yemen-based branch as its most dangerous and has kept up a long-running drone war against its commanders.