Here are the 10 developments in the story:
The Prime Minister and Sonia Gandhi visited the injured at the hospital in Raipur. "First priority is that injured should get best of the facilities. We all have to come together to fight," Dr Singh said. The victims told the Prime Minister that this is a black day for democracy and that the attack will harm grassroot politics. Mrs Gandhi said she appreciates the courage and bravery of Congress leaders in Chhattisgarh. (Read) The PM later announced Rs 5 lakh each as ex-gratia relief for families of those killed.
This morning, the body of Chhattisgarh Congress chief Nand Kumar Patel was found at the site of the ambush. He has been missing since the attack last evening and it was feared that he had been abducted. His son, Dinesh too was found dead this morning. (Read)
Among those dead are Mahendra Karma, one of the Congress's main leaders in Chhattisgarh and a former legislator Uday Kumar Mudaliar. Mr Karma was a local tribal leader, who spearheaded the controversial anti-Naxalite movement Salwa Judum. He had served as the state's home minister when the Congress was in power. He had survived as assassination attempt last year and had Z-plus security.
Vidya Charan Shukla, former Union minister and Chhattisgarh Congressman, was injured in the attack. He is being operated upon at the Medanta Medicity Hospital in Gurgaon. The 84-year-old Congress leader has three bullet wounds in his abdomen and his lungs and liver are reportedly damaged. BJP leader L K Advani visited the hospital to meet Mr Shukla.
At about 3:30 pm yesterday, around 250 suspected Naxals struck a convoy of 40 cars carrying the Congress leaders and others returning from the party's parivartan rally in Sukma. They triggered landmine blasts and then rained bullets at the convoy from vantage pints on hillocks.
The two dozen odd security personnel traveling with convoy returned fire but soon ran out of ammunition. The suspected alleged Maoists then surrounded the convoy, took away the mobile phones of the leaders and then shot them in cold blood. (Track live updates)
There is a shutdown in Raipur today over fears of violence. There have been protests in places and petrol pumps have reportedly been forced to close down. (Watch: NDTV reports from Ground Zero)
Sources say there are indications that the local police and the top Congress leaders of the state might have ignored standard operating procedures that are considered crucial in Naxal-dominated regions. Top political leaders are advised not travel through such routes in a single convoy. Yet on Saturday evening, almost all the top leaders of the Congress' Chhattisgarh unit were travelling in the line of 40 cars returning together after the day's yatra in Sukma district.
The Chhattisgarh government has ordered a judicial inquiry into the attack. "This attack is not party specific but an attack on loktantra (democracy)," said Chief Minister Raman Singh. (Read: Reactions)
Assembly elections are scheduled in Chhattisgarh later this year.