The Lanzhou emergency center in Northwest China's Gansu province said on Wednesday it was investigating whether there was any shortcoming in the response that caused the death of a 3-year-old from carbon monoxide poisoning.

The screenshot of phone records provided by the child's father showed that he made six calls to the emergency medical number from 12:15 pm to 1:06 pm after noticing the poisoning of his child on Tuesday.

The father said no ambulance came after the phone calls, so he and his wife took their child on a taxi to the hospital.

The incident went viral online and netizens questioned whether the local emergency center responded to the situation properly and promptly.

According to a statement issued by the Qilihe branch of Lanzhou Public Security Bureau, police received a report asking for help at 1:43 pm on Tuesday, and the caller said two people had fainted at his home in Shangxiyuan of Qilihe district, including one child who was not breathing.

After receiving the report, the branch immediately sent police to the scene to deal with the situation and helped the caller to send the two victims to the hospital for treatment at 1:57 pm, but the child died after the rescue failed to save him, it said.

The investigation showed that the cause of death was carbon monoxide poisoning caused by improper use of a liquefied gas cooker, said the report.

The caller, the father of the dead child, told Jiankang Daily, a health-related news hub run by the People's Daily, that he found his wife and son had symptoms of carbon monoxide poisoning around noon on Tuesday, and then he dialed the emergency medical number 120 several times, but no ambulance arrived.

Then the couple took a taxi and arrived at the hospital at around 2:30 pm.