Revelation 7:2

7:2 Then I saw another angel ascending from the east, who had the seal of the living God. He shouted out with a loud voice to the four angels who had been given permission to damage the earth and the sea:

Revelation 16:12

16:12 Then the sixth angel poured out his bowl on the great river Euphrates and dried up its water to prepare the way for the kings from the east.