Jailed AAP leader and former Delhi minister Satyendar Jain's medical condition is being investigated, sources said on Friday, a day after he was admitted to an ICU of a city government-run hospital here.

On Thursday, he had collapsed in the Tihar Jail due to dizziness, prompting Chief Minister Arvind Kejriwal to target the Centre over his deteriorating health.

The former Delhi minister was first admitted to the Deen Dayal Upadhyaya Hospital and later shifted to the Lok Nayak Jai Prakash Narayan (LNJP) Hospital due to breathing problems.

Sources in the AAP had said that Jain was shifted to the ICU of the LNJP Hospital and he was "critically ill".

"His medical condition is being investigated," a hospital source said and added that doctors are constantly monitoring his condition.

This is the second time in a week that the former minister has been taken to a hospital. Jain has been in Tihar jail since his arrest by the Enforcement Directorate in connection with a money laundering case in May last year.

The LNJP Hospital is the largest hospital under the Delhi government.

Jain was brought to the emergency department of the LNJP Hospital and doctors examined him, a senior doctor at the hospital had said on Thursday. "Jain has some spinal issues. In the past too he was brought to LNJP Hospital to undergo treatment for it," he had said.

The former minister collapsed in a bathroom of the Tihar Jail due to dizziness. Earlier too, Jain had fallen in the bathroom and had a serious spinal injury, the AAP said.