Students are now being sent home following the incident.
Chichester High School students have now been released following a lockdown on the site this afternoon.
A National Police Air Service helicopter was seen circling the city centre since about 2.30pm and armed police were spotted in Priory Park.
It follows the announcement that Chichester Police were responding to a man seen in possession of a suspected weapon near Litten Gardens. Chichester police have now confirmed on their social media site that they have now detained a man in relation to the incident.
They went on to say "the suspect was reported to be near two schools, we worked with them to take precautions to keep pupils and staff safe while we investigated the report. No threats were made and no one was harmed.
We would like to thank the public for their patience and understanding while we responded to this fast moving incident"