Prince Harry, a member of the U.K. military in Afghanistan is based at Camp Bastion. When he was first stationed there, the Taliban said they were out to kill him, although NATO officials say he was several miles away, and was never in danger during this attack.
On Saturday, two British troops were killed in an attack in Helmand province carried out by a gunman in the uniform of a government-backed militia.
Recent months have seen a string of attacks by Afghan forces against their international counterparts, who are working towards handing over security responsibilities to the Afghans as international troops draw down.
This weekend's attacks come amid turmoil throughout the Middle East, where anti-American protests have flared up, ostensibly in response to the online video mocking the Prophet Muhammad.
An attack on the American embassy in Libya last week led to four deaths, including the American ambassador to Libya. The protests have prompted the removal of U.S. personnel from their posts in Sudan and Tunisia.
U.S. Ambassador to the UN Susan Rice told Jake Tapper on "This Week" the attack was not premeditated, contradicting top Libyan officials who say the attack was planned in advance.
Defense Secretary Leon Panetta says the turmoil raging across the Muslim world will likely continue for days, but the violence appears to be leveling off.
He said the Pentagon has "deployed our forces to a number of areas in the region to be prepared to respond to any requests that we receive to be able to protect our personnel and our American property."
ABC News' Muhammad Lila and The Associated Press contributed to this report.