Washington, Jun 25 (IANS): At least 23 persons were killed as heavy thunderstorms caused sudden flooding in US' West Virginia state, officials said.

Governor Earl Ray Tomblin announced 14 deaths at a news conference on Friday afternoon. By Friday night, the West Virginia Division of Homeland Security and Emergency Management increased the toll to 23, CNN reported.

The victims included a four-year-old boy who was washed away by rapid floodwaters in Jackson county. The child was playing with his sister behind their home when he fell into what a stream that had instantly turned into a rushing current after the relentless storms.

An 8-year old boy from Ravenswood was also killed in the violent storm.

Trees and power lines fell as heavy rains sent creeks and rivers out of their banks late Thursday and early Friday, leaving many stranded residents waiting to be rescued.

Forty-four counties declared a state of emergency Thursday night, primarily in the southeastern part of West Virginia.

Elkview, Clendenin and Frame were hit the hardest by the flooding, officials said.

Tomblin activated 200 National Guard members to assist in eight counties and has authorisation for as many as 300 more to help with the rescue and response efforts, the governor's office said.