The U.S. military on Friday disclosed that it carried out an air strike in Yemen in May, killing four al Qaeda militants, and also revealed three other strikes that had not been previously reported.

The total number of strikes carried out by the U.S. military in Yemen this year against al Qaeda in the Arabian Peninsula (AQAP) is now at nine, the statement said.

The total number of strikes carried out by the U.S. military in Yemen this year against al Qaeda in the Arabian Peninsula (AQAP) is now at nine, the statement said.

"AQAP remains a significant threat to the region, the United States and beyond," it added.

Al Qaeda in the Arabian Peninsula, widely considered the most dangerous branch of the global militant group, took advantage of more than a year of war in Yemen to seize towns along a 600-km (370-mile) stretch of Arabian Sea coastline.

But in April, Yemeni troops backed by a Saudi-led military coalition pushed the group out of its main base in the port city of Mukalla, depriving them of the estimated $2 million a day in revenue from port taxes and fuel smuggling.