For the following passage, identify the tone expressed by the author: 

The darkness of the night was oppressive, the air was thick with fear.
The tone expressed by the author in this passage is ominous and foreboding.
Complete the following task based on the instruction and optional input provided.### Instruction:
For the following passage, identify the tone expressed by the author: 

The darkness of the night was oppressive, the air was thick with fear.

### Output:
The tone expressed by the author in this passage is ominous and foreboding.