Chinese health authorities have not detected any unusual or novel pathogens and provided the requested data on an increase in respiratory illnesses and reported clusters of pneumonia in children, the World Health Organization (WHO) said on Thursday.

The WHO had asked China for more information on Wednesday after groups including the Program for Monitoring Emerging Diseases (ProMED) reported clusters of undiagnosed pneumonia in children in north China.

As per the rule, China responded to the WHO within 24 hours. The WHO had sought epidemiologic and clinical information, as well as laboratory results through the International Health Regulations mechanism.