Twin toddlers were discovered dead inside a hot car after a relative allegedly forgot to drop them off at a daycare center.

Two-year-olds Ariel and Avery were found inside a vehicle after cops responded for a welfare check in Norman, Oklahoma, around 3pm on Thursday.

Both of them were pronounced dead at the scene on the 1000 block of W Brooks Street, according to the Norman Police Department.

‘The initial investigation indicates that the two children were accidentally left in the vehicle for an extended period of time and were later located by family,’ stated the police department.

The toddlers’ parents reportedly said they had left them with a trusted family member who was supposed to take them to a daycare, but forgot.

‘This is truly tragic and has been very hard on the family involved especially where hateful comments are concerned. I hope this will at least show people that it wasn’t intentional and truly an accident,’ a family member told KFOR.

‘This family would just like some peace in this difficult and heavy time.’

The temperature that day exceeded 90 degrees Fahrenheit.

An investigation has been launched into the incident and a medical examiner will determine the toddlers’ cause of death.

Kourtnee Usey, who started a GoFundMe page, said that her cousin Marshall Suter ‘received the most traumatic news any parent could ever receive’.

‘All funds will be used to give these precious little babies the funeral they deserve, and take some weight off of this father’s shoulders after dealing with such a tragic and HEARTBREAKING loss,’ wrote Usey.

‘No one truly knows the pain of losing a child until you are going through it. I know this mom and dad are going through it.’

Ariel and Avery died just over a month after a 14-month-old girl was found dead in a hot car after her grandmother forgot to drop her off at a daycare and instead went to work in Smithtown, Long Island, New York.

There have been at least 31 children who have died in hot cars so far this year, according to Kids and Car Safety.