At least 23 people were killed as a tornado struck Nashville, capital of the U.S. state of Tennessee, on Tuesday morning, said the Tennessee Emergency Management Agency (TEMA). 

Among the victims were two people in Nashville killed after being struck by debris, the police department reported.  

Mayor John Cooper said around 150 people had been transported to medical facilities while some 48 buildings had collapsed in the city, which is the center of the United States' country music scene.  

The Nashville Police Department circulated aerial photographs of many buildings missing roofs and, in at least one neighborhood, homes reduced to piles of rubble standing next to houses that escaped damage.  

"In the hours ahead, we will continue deploying search and rescue teams, opening shelters across the state, and sending emergency personnel to our communities hit hardest," Governor Bill Lee wrote on Twitter.  

U.S. President Donald Trump said that he would visit the stricken areas Friday. "We send our love and our prayers of the nation to every family that was affected, and we will get there and we will recover and we will rebuild and we will help them," Trump said.  

The series of severe storms that passed through Tennessee caused major damage to buildings, roads, bridges, utilities and "businesses in several counties," TEMA said. 

Four poll stations have been transferred as local people started to vote in a Democratic primary to choose a nominee in the 2020 U.S. presidential election in November.  

An airport located in western Nashville "sustained significant damage" due to severe weather, and several hangars were destroyed and power lines were down, the airport said on its website.