CAIRO — Twice in the past seven days, Egypt and the United Arab Emirates have secretly teamed to launch airstrikes against Islamist-allied militias battling for control of Tripoli, Libya, four senior US officials said, in a major escalation between the supporters and opponents of political Islam.
The United States, the officials said, was caught by surprise: Egypt and the Emirates, both close allies and military partners, acted without informing Washington or seeking its consent, leaving the Obama administration on the sidelines.
Egyptian officials explicitly denied the operation to US diplomats, the officials said.
The strikes are another high-risk and destabilizing salvo unleashed in a struggle for power that has broken out across the region in the aftermath of the Arab Spring revolts, pitting old-line Arab autocrats against Islamists.
Since the military ouster of the Islamist president in Egypt one year ago, the new Egyptian government, Saudi Arabia, and the United Arab Emirates have formed a bloc exerting influence in countries around the region to roll back what they see as a competing threat from Islamists.
Arrayed against them are the Islamist movements, including the Muslim Brotherhood, backed by friendly governments in Turkey and Qatar. These movements accelerated amid the Arab Spring revolts.
Libya is the latest, and hottest, battleground. Several officials said US diplomats were fuming about the airstrikes, believing they could further inflame the Libyan conflict at a time when the United Nations and Western powers are seeking a peaceful resolution.
“We don’t see this as constructive at all,” one senior US official said.
Officials said the government of Qatar has already provided weapons and support to the Islamist-aligned forces inside Libya, so the new strikes represent a shift from proxy wars — where regional powers play out their agendas through local allies — to direct involvement.
The strikes have also proved to be counterproductive so far: The Islamist militias fighting for control of Tripoli successfully seized its airport the night after they were hit with the second round of strikes.
US officials said Egypt had provided bases for the launch of the strikes. President Abdel-Fattah el-Sissi of Egypt and other officials have issued vigorous but carefully worded public statements denying any direct involvement inside Libya by Egyptian forces. In private, officials said, their denials had been more thorough.
The officials said that the United Arab Emirates — believed to have one of the most effective air forces in the region, thanks to US aid and training — provided the pilots, warplanes, and aerial refueling planes necessary for the fighters to bomb Tripoli out of bases in Egypt.
The first strikes occurred before dawn a week ago, hitting positions in Tripoli controlled by Islamist-friendly militias, blowing up a small weapons depot and killing six people.
A second set of airstrikes took place south of the city early Saturday, hitting rocket launchers, military vehicles, and a warehouse controlled by Islamist-allied militia.
The second strike might have been motivated by a desire to prevent an imminent capture of the Tripoli airport by Islamist-aligned militia, many of which are based in the coastal city of Misurata and are more tribal than Islamist in orientation.