Aleksanyan, formerly vice president of the now liquidated Yukos, is being held in custody on charges of embezzlement and money laundering. His court trial began earlier today.
In his statement to Russian Prosecutor General Yury Chaika, Khodorkovsky said prosecutors have demanded that Aleksanyan confess to all charges against him in exchange for medical treatment.
Yury Shmidt, a lawyer for Khodorkovsky, said his client intended to continue the hunger strike until Aleksanyan is transferred to a specialized medical treatment facility.
"Khodorkovsky declared yesterday a hunger strike with no water because Aleksanyan is not receiving medical treatment and has not been transferred to a special medical facility," the lawyer said.
However Alla Kuznetsova, a first deputy head of the Russian Federal Penitentiary Service's medical department, said on Tuesday that Aleksanyan is receiving all necessary medical treatment in the detention facility.
"Vasily Aleksanyan is receiving medical treatment in full," she said. "Aleksanyan voluntarily signed an agreement for the treatment, but he refused antiretroviral therapy."
Investigators accuse Aleksanyan of embezzling over 8 billion rubles ($329 million) from Yukos production unit Tomskneft as well as shares worth over 12 billion rubles ($493 million) from other oil companies, and of laundering stolen assets.
