A Northern Ireland school has been closed after a malicious threat was received by email.
Police patrols have been stepped up near Elmgrove Primary after officers said they were investigating a report of "malicious telecommunications" made on Wednesday.
A man aged 33 was arrested in Belfast last night by detectives.
Police Service of Northern Ireland (PSNI) superintendent Darrin Jones said: "The communication was of a threatening nature."
An extensive investigation was launched last night to identify the whereabouts of the individual involved and the PSNI worked closely with Irish police.
Mr Jones added: "Police have deployed additional officers to the local community to keep people safe and to provide visible reassurance."
East Belfast MP Naomi Long said the email had been sent to third parties, not directly to the school.
She added the person behind the message had been extremely reckless.
"I have spoken to the police and have been reassured they are fully investigating a definite line of inquiry.
"I want to praise them for putting extra police around the school, and extend that commendation to the Belfast Education and Library Board and school staff, who took decisive action in handling this situation.
"Elmgrove's closure is only a precaution but it was a wise one to take.
"The receiving of this malicious communication is deeply concerning and brings nothing but stress and disruption to the children of the school, as well as local residents."
Stormont education minister John O'Dowd said he regretted the children' routine and learning had been disrupted by criminal activity.
He said: "To attempt to intimidate any community is unacceptable, but to direct a threat against a school is particularly unfathomable."