However, jail authorities said that they did not get any information from Jagan about his fasting.
"He (Jagan) has not given us any representation on his fast. He has to give in writing and inform, but so far there is no intimation," Chanchalguda jail superintendent B Saidaiah told PTI.
"There is no written communication/letter informing the authorities on which grounds he was resorting to the hunger strike," Saidaiah said adding the Kadapa MP, however, refused to take his breakfast, lunch and dinner.
Resorting to fast by a prisoner is a prison offence as per the state Prison Rules and this matter will be dealt according to the jail manual, he said.
The action likely to be initiated against Jagan includes reduced number of visits by his kin and party colleagues.
YSR Congress honorary president Y S Vijayamma, who had on Saturday called off her indefinite fast opposing proposed bifurcation of Andhra Pradesh after she was forcibly shifted to a hospital in Guntur, had announced that her son and jailed Kadapa MP Jaganmohan Reddy will go on an indefinite fast seeking "justice for Seemandhra people."
As a precautionary measure, security was beefed up around Chanchalguda central prison with deployment of additional personnel from city police and also para-military forces besides the routes leading to jail were barricaded with barbed wires, another senior police official said.
Jaganmohan Reddy has been lodged in Chanchalguda jail since May 27 last year after his arrest by CBI on corruption charges.
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