Peacehaven Community School is closed today after the discovery of a Second World War bomb in the town.
Sussex Police has advised the school to close.
A statement on the school's website said: "Due to the traffic disruption this morning the school will be closed today, until tomorrow morning.
"We will be contacting the parents of those children already in school."
Peacehaven Heights Primary School is also partly closed.
A statement on the East Sussex County Council website said: "There is no access to the INFANT SITE which is located in Roderick Avenue."
Also closed is the Telscombe Cliffs Primary School and Nursery, a statement on its website said.
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