NEW DELHI, Aug. 6 (Xinhua) -- The death toll in lightning strikes in India's eastern state of Jharkhand has risen to 20, official broadcaster All India Radio said Thursday.

The state's Giridih district is the worst-hit, with 11 deaths, the highest number of casualties recorded.

According to the broadcaster, the India Meteorological Department (IMD) has issued an advisory asking people to remain cautious.

"Monsoon has intensified across Jharkhand, bringing a significant change in weather conditions over the past twenty-four hours. Heavy rainfall and lightning have caused widespread damage in several parts of the state. The IMD has issued alerts, advising people to remain cautious," the report said.

The broadcaster said the IMD has issued an orange alert for the next three days in vulnerable areas of north-western and central Jharkhand, warning of very heavy rainfall.