Four schools in the West Midlands were evacuated after receiving bomb scare calls on Tuesday morning.
Three schools in Sandwell and one in Dudley were called between about 9am and 9.30am.
Oldbury Academy, Holly Lodge High School, Bristnall Hall Academy, and Leasowes High School were closed and West Midlands Police carried out checks to search for bombs and "suspicious objects".
West Midlands Police later confirmed that no bombs or suspicious items had been found.
Following checks by our teams at 4 schools across the region this morning, we can confirm that NO bombs/suspicious objects have been found.— West Midlands Police (@WMPolice) January 19, 2016
Schools closed their doors shortly after receiving the bomb calls this morning.
School has had to close today due to unforeseen circumstances. Keep your eye on Twitter/website for updates about tomorrow!— Oldbury Academy (@OldburyAcademy) January 19, 2016
Secondary schools in local area have been advised by the police to close for today. Children all safely out of the building & on way home— BristnallHallAcademy (@BHallAcademy) January 19, 2016
Some parents were angry at a lack of information about the incident.
Speaking to the Birmingham Mail, Parvinder Johal said: "It’s just quite scary because I was getting messages from friends from around 9.30am but wasn’t really sure what was going on.
"A bomb scare is a big deal. My son has special needs so he can’t get home by himself. He needs to be picked up.
"I got a text message from the school but I didn’t know where the children had been moved to. I only got a call from the school at 10.35am. There needs to be a contingency plan for something like this."
Some of the schools were able to reopen after the buildings were checked by police.
Leasowes High School tweeted that lessons would start again "as soon as possible".
We have been reassured by Police that the building is safe for students & staff. Lessons will commence as soon as possible— Leasowes High School (@LeasowesHigh) January 19, 2016
West Midlands Police are investigating the incidents in a bid to find the person responsible for the calls.
Anyone with information that could help officers is asked to call police on 101.
Earlier this month, a school in Blackpool was the subject of a violent threat made on social media.
Montgomery High School, in Bispham, was warned in an anonymous Facebook post that someone would massacre students becasue of alleged bullying.
"On Monday, the bullies will be sorry when I go into school with a gun. I’ll kill as many people as possible," the message said, according to the Blackpool Gazette.
In a series of messages, the poster praised Columbine Massacre gunmen Eric Harris and Dylan Klebold, who killed 12 students and one teacher at their US school in 1999.
He also used the hashtag #MontyMassacre.