US officials say the United Arab Emirates (UAE) has secretly sent warplanes on bombing raids against militias in Libya using Egypt’s air bases.

Speaking on condition of anonymity, the US officials said that the UAE and Egypt have carried out airstrikes in the Libyan capital, Tripoli, over the past week.

“The UAE carried out those strikes,” one of the officials told AFP, adding that the report is “accurate.”

The bombing raids, carried out over seven days, were first reported by the New York Times. Militant sources in Libya also confirmed the strikes.

US sources say the United Arab Emirates, which has spent billions on US-manufactured warplanes and other advanced weaponry, provided the military aircraft as well as aviation crews to bomb targets in Libya, while Cairo offered access to its air bases.

The United States and its European allies have denounced any “outside interference” in Libya. Critics say the stance is ironic since much of the instability in the country is said to have been the direct result of Western involvement.

Meanwhile, neither the UAE nor Egypt has publicly acknowledged any role in the attacks.

In August, an alliance of Libyan militias, known as Fajir Libya, accused the UAE and Egypt of having a hand in two airstrikes targeting their positions in Tripoli.

The alliance announced on August 23 that they were in control of Tripoli International Airport, which has remained closed since July 13 amid skirmishes in the area.

Over the past weeks, the strategic area situated 30 kilometers south of Tripoli has witnessed clashes between Fajir Libya militiamen, partly comprised of men from Misrata, and Zintan forces loyal to former renegade General Khalifa Haftar.

The so-called Islamic militia groups in Libya enjoy financial and military support from Qatar, while UAE, Egypt and Saudi Arabia back their rivals.

Earlier this month, Libya’s newly elected parliament asked the United Nations for military intervention to protect civilians amid relentless clashes. The legislative body also voted to dissolve rival militias, giving them an ultimatum to join the military and police by the end of 2014.

Nearly three years after a popular uprising, Libya is still grappling with rising insecurity despite efforts by the central government to impose law and order.