You can, but you have to start slow to avoid a hot explosion.
DIAGNOSIS: Jumping straight to high speed with hot liquids is dangerous.
FIX: Always start on a low speed setting (1 or 2). Let it run for a minute to let the steam and pressure settle, then you can ramp up to your desired speed. For hot items, use variable speed and run for 1-2 minutes total.
IF THAT DIDN'T WORK: If the soup is too chunky, use the pulse function (turn and hold the dial from O to P) briefly to break it up before switching to a low continuous speed.
HEADS UP: Let the blender come to a full, complete stop before you even think about removing the lid. Hot stuff under pressure is no joke.