LONDON — British Airways is resuming flights to Cairo after security concerns prompted a week-long halt to services.

Flight BA155 departed Friday at 5:20 p.m., marking the resumption of service following “a thorough assessment of the security arrangements.”

British Airways says the “safety and security of our customers and crew is always our priority, and we would never operate an aircraft unless it was safe to do so.”

German-based carrier Lufthansa had also temporarily halted service to Cairo, but resumed flights on Sunday following a one-day suspension due to safety concerns. The German airline’s website shows LH582 took off from Frankfurt after a two-hour delay and arrived in Egypt’s capital Sunday afternoon.

The U.S. warned citizens Friday about travelling to Egypt saying terrorist groups including ISIS committed multiple deadly attacks.

British authorities also warned against travelling to parts of Egypt due to terrorist attacks.