A lawyer for Pollard, 57, said that for over a year his client has suffered from increasingly debilitating and incapacitating medical problems that have resulted in emergency surgeries and other emergency medical procedures.
Pollard's hospitalization brought renewed calls for his release from Israeli Prime Minister Benjamin Netanyahu and President Shimon Peres. Peres dispatched a letter to President Barack Obama asking him to free Pollard.
Democratic and Republican administrations in the U.S. have repeatedly refused Israeli appeals to release the convicted spy.
The White House on Monday said its position has not changed and that the president has no intention to release Pollard.
Pollard was a civilian intelligence analyst for the U.S. Navy when he copied and gave to his Israeli handlers enough classified documents to fill a walk-in closet. Arrested in 1985 after unsuccessfully seeking refuge at the Israeli Embassy in Washington, Pollard was convicted and sentenced two years later to life in prison.
Pollard attorney Eliot Lauer says his client's medical problems have included loss of balance, fainting, repeated falls, extreme dizziness, severe nausea and excruciating abdominal pain in the area of the gall bladder and pancreas. Lauer says excruciating pain was the immediate problem that caused the current hospitalization and that doctors are awaiting the results of tests to try to locate the nature of the problem.
In accordance with Bureau of Prisons policy, BOP spokeswoman Traci Billingsley declined to give the reason for Pollard's hospital admission.