"Doctors are treating him. He is critical. And doctors are doing their best to restore his health," Nadda told reporters.

Prime Minister Narendra Modi, Vice President M. Venkaiah Naidu, Home Minister Rajnath Singh, BJP brass, including its President Amit Shah, Chief Ministers and leaders of other parties, including Congress President Rahul Gandhi, made a beeline to the hospital where he was admitted on June 11.

Earlier in the day, an hospital statement said there was no improvement in his condition since Wednesday evening when his health deteriorated.

"Vajpayee's condition continues to be the same. He is critical and on life support," said the statement from the All India Institute of Medical Sciences (AIIMS).

Prime Minister Narendra Modi had visited the AIIMS on Wednesday night, too, to take stock of the situation and enquire about Vajpayee's condition.

Vajpayee, a diabetic patient, is undergoing treatment at AIIMS since June 11. He was admitted to the hospital for what doctors described as a routine check-up.

The 1924-born leader is under the supervision of Randeep Guleria, a pulmonologist and currently the Director of AIIMS.

Guleria has served as personal physician to the three-time Prime Minister for over three decades.

The former Prime Minister, whose birthday on December 25 is celebrated as Good Governance Day, was honoured with the Bharat Ratna in 2014 at his home.