St Andrew's Cathedral School in Sydney's CBD was placed in lockdown on Thursday afternoon as police patrolled the perimeter after the school was the target of threatening messages on social media.

The Anglican day school is the third Sydney school to be subjected to social media threats this week, after East Hills Boys High School in Panania and Sir Joseph Banks High School in Revesby were placed in "lock-out" by police on Tuesday.



Police confirmed threats had been made to St Andrews on Thursday but would not comment on whether the threats were terrorism related.

Lockdown: St.Andrews Cathedral School. Credit:Brendan Esposito

"NSW Police have been made aware of threatening information sent to a school in the CBD today," a spokesperson for NSW police said.

"The school has been placed in lockdown as a precaution with officers patrolling the area."