According to police, BJP MLA from Dantewada Bheema Mandavi and four personnel of District Force (DF), deployed in security of the MLA, were killed in the powerful IED blast executed by ultras.
The attackers also allegedly opened fire at the occupants of the convoy.
"Chhattisgarh will witness Lok Sabha polls in the first three phases- April 11, April 18 and April 23 for its 11 Parliamentary constituencies".
Chhattisgarh director general of police (Naxal Operations) Girdhari Nayak said, "The BJP MLA was returning after an election rally".
Prime Minister Narendra Modi "strongly" condemned the attack, saying the sacrifice of those killed will not go in vain.
This was the first Maoist attack in Chhattisgarh since the Congress assumed power in December last year, ending 15 years of BJP rule in the state.
"My tributes to the security personnel who were martyred", he posted on Twitter. "The sacrifices of these martyrs will not go in vain", the PM tweeted.
Mandavi had spoken out against the Naxal attack on a Doordarshan crew in October, 2018 in which cameraperson Achyuta Nanda Sahu and two police officers were killed in Dantewada.
On 4 April, four BSF personnel were killed in Bastar's Kanker district after being ambushed by Maoists.
"The BJP MLA was going to Nakulnar after addressing an election meeting at Bacheli in his bullet proof vehicle along with his PSOs when Maoists triggered the IED blast", said a senior police officer.
Another senior police officer said the explosion left the vehicle a twisted ruin, and the bodies of some victims unrecognisable.
The Maoists had called for boycotting the elections. In view of the lack of adequate security on the route, police had asked the BJP lawmaker against undertaking the journey but he ignored the warning. Congress described it as an "unfortunate" incident.