Bright light observed moving erratically at great speeds. Acceleration and deceleration of craft was great.I was on holiday in Egypt, at the top of Mt Sinai, viewing the sunrise. In the twilight before sunrise I noticed a single, fairly dim white light, which initially appeared to be a star, in the direction of the sunrise position. The light then began moving left to right to left in a mainly horizontal plane. The movement seemed quite random, i.e. the object did not appear to be travelling toward any particular destination. As an example of the motion observed; the craft would sometimes move to the right, stop, then continue moving to the right. Other times it would move to the right, stop, then begin moving to the left.The speed of the craft varied, from a slow drift, to a speed so great that it is difficult to explain how this speed was achieved. The craft accelerated extremely rapidly, from an apparent standstill. The craft also decelerated to a stop almost instantaneously, even after it had just accelerated to a great speed. This rapid motion was all in a horizontal direction.This went on for 20 mins or more. All the while, the craft was very gradually drifting higher in to the sky and to the right. This was happening at the same time as the sun came closer to rising and the twilight became brighter.When the sun rose, the craft seemed to disappear by fading away. I am not sure if this was caused by the brightness of the sun washing out the light from the craft, or if the craft was in fact moving further away.I estimate the craft was 10-20km away, and at least 10,000ft altitude. I take these estimates from the fact that the craft occasionally disappeared behind clouds. The clouds appeared to be at quite high altitude.I took some photographs of what I saw, will need to check the developed pictures to see if the object is clearly visible in the photo as it was quite distant and the camera is only a pocket 35mm type.