Sunday morning, august 9th, ( 319am) from the cargo ramp of ted stevens int'l airport, in anchorage, ak, me and another pilot were just about to start engines when i spotted an anomaly near the departure (left of center) end of runway 33 at approximately 150-200 feet agl. it was a rapidly flashing white strobe (3 pulses then a short pause - less than 1 second) and it continued to remain in the same spot. i asked the other pilot if they saw what i was seeing. they confirmed they were seeing it too. i then called the tower and reported what i assumed was a drone. tower said they could not see it due to the intensity of the airfield ramp lighting between his position and the position of the anomaly. i turned on our tcas to see if it was an aircraft squawking with its transponder. nothing. i tried using the radar at a high intensity setting. nothing significant. duration of observation about 7 minutes. we stopped our observation and proceeded with our engine start while the port authority sent vehicles to investigate. during this time, our focus was on engine start and not on the anomaly. the airport was temporarily closed. the port authority contacted the exterior perimeter police and the interior port authority to investigate. the port authority arrived at the scene approximately 12 minutes my first observation. they surveyed the area and nothing observed. police were also in the area at the outskirts of the airport. nothing was discovered, no people or vehicles. after the police and the port authority said they saw nothing, we were asked if we would mind waiting a few more minutes before we departed. after we waited about 7 minutes the tower reopened the airport and asked the b747 who was next for departure if they were comfortable with taking off on runway 33. they departed. we soon after them.