LANZHOU, July 3 (Xinhua) -- The Maijishan scenic area, home to the UNESCO-listed heritage site Maijishan Grottoes, in northwest China's Gansu Province, has been temporarily closed to visitors since Thursday morning due to heavy rain in the region.

Zhang Hui, deputy director of the Maijishan scenic area management committee, said the closure was prompted by concerns over cultural heritage protection and visitor safety.

The scenic area will remain closed until further notice and visitors who purchased tickets will receive refunds, Zhang added.

The scenic area in the city of Tianshui has recently entered its peak tourist season, receiving around 10,000 visitors per day.

Hu Junjian, a researcher with the Maijishan grottoes art research institute, said that the Maijishan Mountain is composed of red glutenite with a relatively loose structure and prolonged heavy rainfall increases the risk of falling rocks.

Staff have been dispatched to closely monitor high-risk areas and implement preventive measures, Hu added.

Torrential rains lashed parts of Tianshui from Wednesday to Thursday morning and are forecast to continue in the next 24 hours, according to the Gansu Meteorological Service.

Following heavy rains in Tianshui and three other cities, the provincial water resources department has raised the flood emergency response to the third-highest level.

In Wudu district in Tianshui's neighboring city of Longnan, precipitation reached 220 mm in the 24 hours leading up to 7 a.m. Thursday, the Gansu Meteorological Service said.

Local authorities have issued orange alerts, the second-highest level in a four-tier weather warning system, for flash floods and geological disasters in Tianshui and several other regions.

The Maijishan Grottoes, dating back over 1,600 years, were inscribed on the UNESCO World Heritage List in 2014. The site features 221 caves carved into a cliff, linked by 1.5 km of aerial walkways, with the highest pathway reaching over 70 meters above ground.