US troops are helping United Arab Emirates forces push Al-Qaeda-affiliated forces from a Yemeni port, and the Pentagon has stepped up air strikes against the jihadists in the war-torn country.

Defense Department spokesman Navy Captain Jeff Davis's confirmation of the deployment marked the first time the Pentagon has publicly acknowledged that US troops are operating inside Yemen.

Davis said a "very small number" of military personnel has been working with Yemeni and Arab Coalition forces -- especially the Emiratis -- in recent weeks as they pushed Al-Qaeda in the Arabian Peninsula (AQAP) fighters from the port city of Mukalla, which they seized in April last year.

"This is of great interest to us. It does not serve our interests to have a terrorist organization in charge of a port city, and so we are assisting in that," the spokesman added.

He said the troops were helping the Emiratis with "intelligence support," but declined to say if they are special operations forces.

While the number of US personnel on the ground is limited, the United States is also offering an array of assistance to partners in Yemen, including air-to-air refueling capabilities, surveillance, planning, maritime security and medical help.

The US Navy also has several ships nearby, including an amphibious assault ship called the USS Boxer and two destroyers.

AQAP took advantage of the chaos of fighting between pro-government forces and Iran-backed rebels to expand its control in southern Yemen, including the seizure of Mukalla.

The Pentagon announced it has carried out a recent string of strikes on AQAP in recent weeks, outside of Mukalla.

"We have conducted four counterterrorism strikes against AQAP since April 23, killing 10 Al-Qaeda operatives and injuring another," Davis said.

The United States periodically conducts such attacks on AQAP targets in Yemen, including a strike in March on a training camp that killed more than 70 fighters.

AQAP, which has long been entrenched in Yemen, is regarded by Washington as the network's most dangerous branch and has carried out deadly attacks on the West.