A 16-year-old boy has been arrested after he allegedly threatened to kill another teenager.
Threats to kill were made online towards a pupil at Christ the King Catholic High School in Preston, said police.
There was a visible police presence at the school in Lawrence Avenue yesterday.
A police spokesman said: "We were called at 10.32am yesterday (Monday, March 18) to reports of a concern for safety.
"It was reported that threats had been made over social media towards a pupil at Christ the King High School on Lawrence Avenue in Preston.
"Safeguarding measures were put in place and there was a heavier police presence in the area for reassurance purposes.
"Section 60 powers were also authorised in the Frenchwood and Avenham areas until 5pm on Monday, March 18.
"A 16-year-old boy from Preston has been arrested on suspicion of threats to kill and is currently in custody.
"We are treating this as a targeted threat and do not believe there is any wider concern for the public."
Damien Callagher, head teacher at the school, said : "We would like to reassure all members of the school community following reports in the local media.
"As a precautionary measure police were contacted following threats being made at the weekend against one of our students.
"Police were present at the end of the school day and students left for home safely. At no time was the school in lockdown."
The school was open as normal today.