Around 90 primary schoolchildren in South Africa were sent to hospital after eating muffins thought to be laced with cannabis.

Officials said the pupils bought the muffins from a street vendor on their way to Pulamadibogo Primary School, north-west of Pretoria.

They experienced nausea, stomach pain and vomiting - and three girls are still in hospital.

Two people have been arrested and face charges of attempted murder.

The suspects, aged 21 and 19, will appear before Soshanguve Magistrate's Court on Friday, police said.

The Gauteng provincial education department said teachers had called an ambulance after noticing "strange behaviour" from children in class.

It said the incident had caused considerable distress to parents who were worried about their children's safety.

Police, who are conducting a toxicology report to confirm if cannabis was used, say more than 90 pupils received the muffins and suffered "serious pains".

They were all sent to nearby medical facilities, and "about 87" have been discharged, the education department said in a statement.

"Only three girl learners remain in hospital, and they are still receiving the necessary medical attention to return to health," it said.

Earlier this year, the Democratic Alliance (DA) party called for better vetting processes for street vendors, after eight children were admitted to hospital having eaten so-called "space cookies" outside their school.

The party's spokesperson Khume Ramulifho also said he would pressure the provincial government to improve safety measures at school.