More than 20 visitors at Nanzenji temple in Kyoto complained of throat and other pains Wednesday morning following the release of a strange chemical smell. Four people were hospitalized, but none sustained life-threatening injuries, local authorities said.

It is not yet known what caused the pungent odor, temple officials said, but it is believed to have emanated from around a toilet located near the Buddhist temple's main building. Around 70 people evacuated the temple, which is designated as a national treasure.

Visitors received emergency medical treatment on the temple grounds and around a dozen ambulances and fire engines were dispatched to the site.

An official of the temple called firefighters around 11:30 a.m. after one of the visitors reported a "strange smell."

"Some people around me suddenly started coughing or even shedding tears. I immediately ran away from the site," said Yoshie Iwata, a 42-year-old visitor from Sakai, Osaka Prefecture.

The temple closed its doors to visitors following the incident but reopened Thursday.

The temple opened in 1291 and is the head temple of the Nanzenji school of Rinzai Zen Buddhism.