Lightning strikes continue to kill people in India's eastern state of Bihar as floods have affected over 400,000 people in eight districts, officials said on Wednesday.

According to officials at Bihar disaster management department, 18 people lost their lives in the past 24 hours due to lightning strikes in nine districts of the state.

The deaths have taken place in Banka, Jamui, Nalanda, Nawada, Gaya, Bhagalpur, Jehanabad, Lakhisarai and East Champaran.

"Six people were killed in Banka district, three each in Jamui and Nalanda, and one each in Nawada, Gaya, Bhagalpur, Jehanabad, Lakhisarai and East Champaran districts," an official at Bihar disaster management department said.

So far close to 200 people have been killed in lightning and thunder strikes across the state over the past several weeks.

Disaster management officials said the victims were either working inside their fields or had taken shelter under trees at the time of lightning.

Chief Minister of Bihar Nitish Kumar has expressed grief over the deaths in lightning strikes across the state and announced monetary relief for victim families.

Kumar has appealed people to take care during bad weather conditions and avoid venturing out at the time of lightning and thunderstorms.

He also urged people to strictly follow the precautionary measures issued by the disaster management office for bad weather conditions.

The meteorological department officials have cautioned people to remain vigilant as more rain and lightning strikes were expected during the next 24 hours in different parts of the state.

People have been advised to remain indoors during bad weather conditions.

Meanwhile, floods have wreaked havoc in the state's eight districts, affecting 413,952 people.

The floods have inundated Sitamarhi, Sheohar, Supaul, Kishanganj, Darbhanga, Muzaffarpur, Gopalganj and East Champaran.

Authorities have set up relief camps in Supaul and Gopalganj for people.

Reports said people in other affected districts have taken shelter with their friends and relatives.

Officials said water in Ganga, Baghmati, Kamlabalan and Mahananda rivers was flowing above the danger level at several places.

A spokesman said local government officials were inspecting relief and rescue operations in the flood-affected areas of the state.

"The district magistrates in the flood-affected areas are reviewing preparedness and undertaking visits to the affected areas to ensure affected people are taken care of," an official at information and public relations department in Bihar said.

According to the official, the disaster response force personnel were present in the flood-hit districts to carry out rescue work.

Floods have also wreaked havoc in India's two northeastern states of Assam and Meghalaya.