Two children who attended the same preschool in Kawasaki died within a week earlier this month, possibly due to an infectious disease, city officials said.

The city said Wednesday it is examining blood samples from the children but has yet to detect any virus that could be tied to the deaths. The children attended the Daishi Kindergarten.

According to the city, a 4-year-old girl died on June 6 after she was diagnosed with acute inflammation of the stomach and intestine. She had a fever and complained of nausea starting around June 4 and her condition got worse on the early morning of June 6.

On June 12, a 4-year-old boy died after exhibiting symptoms such as a fever and muscle cramps in the morning, the city said.

Family members of the two children have not developed similar symptoms, the city said.

About 200 children attend the kindergarten. Some have shown symptoms of a cold, but no indications of serious conditions have been reported.

"Even if we find that the children died of a contagious disease, we presume it is not anything like a new type of flu," Noboru Sakamoto, a senior official of the city's health and welfare bureau, told reporters.

Following the reports of the deaths, the kindergarten voluntarily closed from Tuesday through this coming Sunday.