Israel's prime minister has asked Barack Obama, the US president, to pardon an American who spied for Israel.
The White House said on Tuesday it was reviewing the request from Binyamin Netanyahu.
Pollard, a former analyst in the US navy, is serving a life sentence for passing thousands of secret documents about US spy activities in the Arab world to Israel between May 1984 and his arrest in November 1985.
"Two weeks ago I received a letter from the prison, from Jonathan [Pollard], which asked me to request openly - I emphasise openly - as prime minister of Israel, for the president of the United States to make an official request for his release," Netanyahu told parliament on Tuesday.
"I would like to read to you the letter that I sent to President Obama in the matter of Jonathan.
"'Honourable president, in the name of the Israeli people I am turning to you to request a pardon for Jonathan Pollard ... At the time of his arrest Jonathan was acting as an agent of the government of Israel, although Israel did not in any way direct its intelligence efforts against the United States.
"'[Israel] acted mistakenly and totally unacceptably ... Both Mr Pollard and the government of Israel have repeatedly expressed their regret at these actions and Israel will keep to its pledge that such things will never happen again.'"
The issue of Pollard, a US-born Jew who was given Israeli citizenship while in prison, has been a thorn in the side of relations between Israel and its main ally, Washington.
His arrest sparked a crisis in ties that only ended with Israel promising to end all espionage activities on US soil.
But Israelis say Pollard's punishment and the longstanding US refusal to commute his sentence have been particularly harsh, given that he gave information to a friendly nation.
Israeli prime ministers have repeatedly tried, in vain, to secure Pollard's release.
Netanyahu last month announced his intention to make a public plea to Obama for Pollard's release and the US state department issued a non-committal response after Netanyahu announced his intentions.
"If such a request were formally made, there's obviously a legal process that would be undertaken to evaluate it," Philip Crowley, US state department spokesman, said at the time.
Crowley did not rule out the prospect that Pollard's case could be looked at in a broader light.
"In the context of advancing Middle East peace, if either the Palestinians or the Israelis want to raise with us issues of importance to them, we will consider all of this as we try to get them to an agreement," he said.
Netanyahu's decision to appeal publicly to Obama came after a meeting with Pollard's wife, Esther, in Jerusalem last month, during which she gave Netanyahu a letter from her husband.
Netanyahu at the time said the decision "was made following a series of talks and contacts which the prime minister and his representatives have held on the issue in recent months with senior US administration officials".