Jerusalem (CNN) -- Israel's Prime Minister Benjamin Netanyahu publicly appealed to U.S. President Barack Obama on Tuesday to release convicted spy Jonathan Pollard, promising Israel would never again spy on the United States in the way Pollard did.

"Jonathan has suffered greatly for his actions and his health has deteriorated considerably," Netanyahu argued. "The people of Israel will be eternally grateful" to Obama if he pardons him, he added.

"Both Mr. Pollard and the government of Israel have repeatedly expressed remorse for these actions, and Israel will continue to abide by its commitment that such wrongful actions will never be repeated," Netanyahu said in a speech in Israel's parliament, the Knesset.

"At the time of his arrest, Pollard was acting as agent of the Israeli government. Even though Israel was in no way directing its intelligence efforts against the United States, its actions were wrong and wholly unacceptable," Netanyahu said, reading aloud the letter he sent to Obama.

The White House has received the letter and "will review it," White House spokesman Tommy Vietor said Tuesday.

Netanyahu agreed in December to formally request the release of Pollard, a former U.S. Navy intelligence analyst who was caught spying for Israel in 1985 and was sentenced in 1987 to life imprisonment.

He has already served 25 years of his sentence.

In December, Pollard's wife hand-delivered a letter from Pollard to Netanyahu, pleading for help.

Many Israeli leaders over the years have requested Pollard's release, Netanyahu observed in his letter to Obama.

"Since Jonathan Pollard has now spent 25 years in prison, I believe that a new request for clemency is highly appropriate," he said.

"Jonathan Pollard has reportedly served longer in prison than any person convicted of similar crimes, and longer than the period requested by the prosecutors at the time of his plea bargain agreement," he added.

The Central Intelligence Agency declined to comment on Netanyahu's request for Obama to release Pollard.

Then-CIA Director George Tenet threatened to resign in 1998 if then-President Bill Clinton pardoned Pollard, Tenet wrote in his autobiography.

Netanyahu, who was prime minister at the time, offered to make concessions in peace talks with the Palestinians in exchange for Pollard's release, Tenet said.

CNN's Guy Azriel, Jill Doughterty, Pam Benson and Izzy Lemberg contributed to this report.