The United States refuses to release an American who spied for Israel because it suspects the Jewish state concealed the existence of other spies, a former Israeli envoy to Washington said on Monday.
Speaking to Israeli public radio, former ambassador Itamar Rabinovich said Washington never believed that Jonathan Pollard -- an American who is serving time for passing secret US documents to the Jewish state -- acted alone.
"The Americans suspect that Jonathan Pollard was not alone, that there were other Pollards and that Israel, despite all its promises, did not reveal all its cards," he said.
"They (punished) Israel on the back of Pollard and expressed their anger more with Israel than with Pollard," he added.
Asked about the possible existence of other Israeli spies in the United States, Rabinovich would say only: "I fear so."
And asked if Israel had come completely clean about details of the Pollard affair, he said: "To my knowledge, Israel hasn't said everything."
In a later email to AFP, Rabinovich said some of his comments to the radio station had been "misunderstood" and that the remark "I fear so" referred to his concern that opponents of Israel meant to spread such an allegation.
On the degree of Israeli disclosure to Washington, Rabinovich said that his comment was intended to convey his lack of familiarity with events which took place before his appointment in late 1992.
"At all the meetings I attended, no American complaint against Israeli officials was raised," he said. "Rumours, malicious rumours, were something else."
Pollard, a former navy analyst, was sentenced to life in prison in 1987 for having passed classified US defence documents to Israel between May 1984 and November 1985 when he was arrested.
He was granted Israeli citizenship in 1995, and three years later he was officially recognised as an agent working for the Jewish state, which promptly launched a bid to bring him to Israel.
This week, nearly 70,000 Israelis, including prominent intellectuals, signed a petition calling on President Shimon Peres to use a trip to the United States this week to pressure his US counterpart President Barack Obama for Pollard's release.
"Any pardon depends on the American president," Peres told Israeli public television on Monday from Washington.
"I will speak to him, and explain my point of view while underlining the humanitarian aspect of my demarche," he said.
Many Israelis feel that Pollard's sentence was too harsh given that he was providing information to a "friendly" nation.