NEW DELHI, India (CNN) -- Former Indian prime minister Atal Bihari Vajpayee, who has been on a ventilator since Friday, is responding to his treatment, according to his doctors.
D.K. Sharma, the medical superintendent of the All India Institute of Medical Sciences, announced Sunday that Vajpayee may be required to remain hospitalized for another week.
"His condition is being monitored closely. All his key parameters, like the blood pressure, the kidneys and the heart, are stable," Sharma said.
Vajpayee, 84, was admitted to the hospital in Delhi on Wednesday. He was put on a ventilator after his lower-track respiratory infection worsened.
Vajpayee served as India's prime minister twice for two weeks in May 1996 and again from March 1998 to May 2004. He represented the Hindu nationalist Bharatiya Janata Party (BJP).