Rashtriya Janata Dal (RJD) chief Lalu Prasad Yadav's health has deteriorated and will be shifted to AIIMS in Delhi for further treatment, several media outlets reported. His son, RJD leader Tejashwi Yadav and family are likely to accompany him.

Lalu Prasad Yadav, who is serving a sentence after he was convicted in the Bihar fodder scam, is being treated for a lung infection at a Ranchi hospital. A medical board of the jail has allowed his transfer to Delhi for treatment.

Speaking to reporters, Tejashwi Yadav said he would speak to Jharkhand Chief Minister Hemant Soren and ask for better treatment for his father.

"We want better treatment for him, but it is for doctors to analyse what treatment can be provided here, after all the test reports come. His situation is serious. I will meet the Chief Minister on Saturday," he said.

"He has already undergone heart surgery earlier and only 25 per cent of his kidney is functional. He has also been diagnosed with pneumonia. He is facing difficulty while breathing," the RJD leader added.

Lalu Yadav has been in jail since December 2017 after being convicted. He has served most of his jail sentence in Jharkhand at the Rajendra Institute of Medical Sciences hospital.

His son Tejashwi Yadav has been leading the RJP in his absence and has been credited with the party's strong performance in the Bihar election last year.