Close-up: Air strike warning footage
Israel has urged thousands of people in east and north Gaza to leave their homes as it continues air strikes, which it says are aimed at stopping Hamas rocket attacks.
Palestinian officials say at least 211 people have died in Israeli raids, including 10 killed overnight and four children who died later on Wednesday.
Israel says it is trying to minimise civilian casualties by issuing a variety of warnings - but how effective are they?
The BBC examines footage from both sides.
- From the section Middle East