The White House on Monday rejected calls from Israel to release convicted Israeli spy Jonathan Pollard from prison, despite pleas from the country´s top leaders amid reports he had fallen ill.

News media in Israel reported Monday that President Shimon Peres had sent a letter to Barack Obama appealing to the US leader to free Pollard, in prison since 1985 for passing on secret US documents to Israel.

Israeli Prime Minister Benjamin Netanyahu also urged the United States to release Pollard -- a gesture he had hoped could coincide with Sunday´s Passover holiday.

"It is time to release Pollard. The Festival of Freedom of all the Jews should turn into Pollard´s private one," Netanyahu said in a statement.

"I have done much for his release, and will continue to act for it," he said Sunday.

But Tommy Vietor, White House spokesman on foreign policy matters, told reporters Monday that the United States had not altered its stance on keeping Pollard behind bars.

"There´s no change in our position," Vietor, spokesman for the White House´s National Security Council (NSC), told reporters.

On Friday, Israeli media reported that Pollard, 57, had been rushed to hospital near his North Carolina prison.

The former US Navy analyst passed thousands of secret documents about American spy activities in the Arab world to Israel between May 1984 and his arrest in November 1985.

He was granted Israeli citizenship in 1995 and was officially recognized by the Jewish state as an Israeli spy in 1998.

Israelis have said that Pollard´s punishment and the long-standing US refusal to reduce his sentence have been particularly harsh, considering that he gave information to a friendly nation. (Copyright © 2012 Agence France Presse. 04/09/12)