A mother who suffocated her three-year-old daughter with a pillow and tried to slice her teenage son’s neck with shards of broken glass has been seized by police.

Suspect Clelida Silva de Almeida, 34, reportedly first smothered her daughter and then attacked her son with shards from a broken mirror.

She was arrested at her mother’s home in Rondonopolis, Mato Grosso state, Brazil, earlier this week.

The drama started in the early hours of the morning when De Almeida’s mother was woken by her grandson’s terrified screams.

After forcing her way into the boy’s barricaded bedroom, she found the 15-year-old covered in blood as his mother stood over him holding two glass shards.

The grandmother restrained her daughter and told her grandson to run to ask for help.

Police arrested Clelida, while paramedics found three-year-old Ayla Jenifer dead in another room.

The teenage boy was taken to hospital for treatment for a cut to the neck. He was last reported to be out of danger.

His mother was taken to the local police station. At the time of reporting, she was due to attend a custody hearing.

The family said that even before the crime, Clelida had started to show signs of psychiatric problems and already had a medical consultation scheduled.

The police will investigate the case.