Dr Yatin Mehta, Chairman of the critical unit of Medanta Hospital here where 84-year-old Shukla is undergoing treatment since May 26, said the leader is serious and "it was matter of concern that he is serious all the time".
"I can't tell you details now but yes he is serious and it now it is a matter of concern. I can't tell you more than that," said Mehta.
A spokesperson of city-based Medanta Hospital said though Shukla had shown marginal improvement a week ago his condition again decorated following an infection and he still remains critical, he said.
The Congress leader was airlifted to Medanta Hospital in Gurgaon from Raipur May 26, a day after the attack which eliminated almost the entire top leadership of Chhattisgarh unit of Congress.
Maoists had ambushed a convoy of Congress leaders in Chhattisgarh's Bastar district on Saturday, killing 27 people including PCC chief Nand Kumar Patel, his son Dinesh, senior Congress leader Mahendra Karma and ex-MLA Uday Mudaliyar and injuring Shukla and 36 others.