An officer from the South East Counter Terrorism Unit has said that the packages left near a number of armed forces recruitment offices "pose a very low level threat and are unlikely to cause significant harm or damage".
Detective Superintendent Stan Gilmour said the contents of the packages were being sent for forensic examination.
He added: "When a suspect package is reported we have a routine response which means we may need to evacuate the area if necessary until we can be sure it poses no threat to the public."
More top news
A man accused of stabbing his father to death during a row over food has been arrested by police.
The UK's biggest ambulance service is to become the first in the country to be placed in special measures.
Footage of an armed burglar crawling on the floor of a couple's bedroom while they slept just feet away has been released by police.