An Israeli cabinet minister is due to visit to incarcerated spy Jonathan Pollard in the United States for the first time in years.

Moshe Kahlon, the Minister of Telecommunications and Social Services and a Likud party leader, is scheduled to visit Mr Pollard at Butner Prison in North Carolina on Wednesday.

The visit has been cast into doubt by Pollard family members and supporters, who said this week that due to ongoing illnesses, he may not be able to receive visitors.

However, the appointment is the latest sign that the campaign for an amnesty for the Israeli spy, convicted in 1985, is gathering steam, with high-profile American politicians joining in.

The imprisonment of the former United States Navy intelligence analyst has long been a sensitive issue between the two allies but, two months ago, Prime Minister Binyamin Netanyahu wrote an open letter to President Barack Obama, requesting that he pardon Mr Pollard.

Mr Pollard's supporters have managed to enlist an impressive number of former and serving US politicians and officials in the campaign for his release.

Among them are former Secretary of State George Shultz and former CIA Director James Woolsey. In recent weeks, former vice president Dan Quayle and former congressman Lee Hamilton, who was chairman of the Congress Intelligence Committee when Pollard was sentenced, have joined the call.

This week, another weighty voice joined in. Former secretary of
state and national security adviser Henry Kissinger issued a statement calling upon President Obama to
grant clemency.

Mr Kissinger wrote that Mr Pollard had served a heavy enough punishment and that "justice would be served by commuting the remainder of Mr Pollard's sentence of life imprisonment."