The fire service said firefighters had immediately provided emergency care to the two young children after rescuing them.
Medics worked “rapidly to administer advanced life support to both children but tragically they were both confirmed dead a short time later”, West Midlands Ambulance Service said.
West Midlands Police said they had cordoned off the scene as officers work to establish the exact circumstances of the fire.
The cordon is expected to remain in place for some time at the property, which was extensively damaged, as inquiries continue.
“Our thoughts are with the children’s loved ones and all those impacted by this heartbreaking incident,” a force spokesperson said.
