A mother has been detained following the deaths of two pairs of twin boys, aged three and four, in a house fire in south London.

According to the London Metropolitan Police, the 27-year-old is being held on suspicion of child neglect.

Firefighters were called to a mid-terrace property on Collingwood Road in Sutton soon before 7 p.m. on Thursday. According to Richard Mills, deputy commissioner of the London Fire Brigade, they discovered a "very well-developed" blaze with the four boys inside.

"I can confirm that they are two sets of twins, ages four and three," he told reporters at the site on Friday.

When asked if there were any other occupants in the house, he stated, "Upon my arrival, there were four children in the house."

Scotland Yard stated that all of the boys were linked.

They were treated at the scene before being transferred to two south London hospitals, where they were confirmed dead.

In a statement issued Friday morning, the force verified the arrest and stated that the woman remained in police custody.

Mr. Mills stated that firefighters using breathing apparatus entered the home, took the four youngsters, and performed cardiopulmonary resuscitation on them.

The fire was extinguished at 8.36 p.m., and the reason is being investigated.

"Entering a building and rescuing lives is always a tough place to be," he said of the firemen involved. The children's age, their infancy, will have a significant effect on them."

Counseling is being provided to crew members who went, he added.

Andy Roe, the London Fire Commissioner, had stated that the children's deaths had left "everyone numb with profound sadness."