Two toddlers died on Monday in the Bronx after they were found unconscious in their beds in the middle of the night, the police said.

The siblings — Olivia Gee, 2, and Micha Gee, 3 — were not breathing when they were discovered by their mother’s boyfriend at about 1 a.m. Monday after he went into their bedroom to check on them, the police said. They had been put to bed at 8:30 p.m.

No foul play is suspected, although the investigation is continuing, the police said. The bodies are with the Office of the Chief Medical Examiner and will undergo autopsies to determine the cause of the deaths.

The children were taken to Montefiore Medical Center, where they were pronounced dead. Both had a history of asthma, the police said.