Despite the assurance US President Barack Obama that securing the release of US-Iranian pastor Saeed Abedini from an Iranian prison remains a top priority, the pastor is is still faced with the possibility of extended jail time as he faces pressure to renounce Christianity.

The American Center for Law and Justice (ACLJ) disclosed that jail authorities are threatening the pastor with fresh charges if he does not abandon his Christian faith, reported Morning Star News. 

"They have said, 'Don't think you'll get out after eight years. We'll add additional reasons to keep you. That's the kind of threat, in conjunction with an uptick of, 'If you recant, if you return to Islam, we will let you go.' That's not anything new, but it's a very concentrated, intense time in the prison at present,"  ACLJ international director Tiffany Barrans said.

Barrans added that authorities are also using the persecution of other Christian prisoners to emphasise their point.

Late last year, Pastor Farshid Fathi was sentenced to an additional year in prison after authorities accused him of having alcohol in prison. The pastor may also face an additional two year jail term for allegedly insulting an imam from another ward. These events, she said, are taking its psychological toll on Abedini.

Barrans speculated that the added pressure on Abedini may be connected to international efforts, of which the US is a part, to limit Iran's ability to produce nuclear weapons.

"There's just been an increased amount of activity and tension and threats and singling out of Saeed as an American in the prison since the framework agreement was reached between the countries. These nuclear negotiations have dramatically complicated the situation – as much as our government insists that he is not a political pawn, and that they will not allow him to be used as a political pawn," she said.

Still, if the US government does not secure Abedini's release while negotiating the nuclear agreement, there may not be a second chance to get him out. 

Abedini's family has earlier appealed to the government to facilitate the return of the pastor to the US as soon as possible after he reportedly suffered injuries as a result of physical abuse in the prison.  He also reportedly been left traumatised by the recent execution of fellow prisoners.

The pastor is serving an eight-year prison sentence for charges of "undermining national security" by working with Christian house churches, meeting with Christians inside private homes, and "attempting to sway Iranian youth away from Islam."

The ACLJ is helping the pastor's family campaign for his release as he approaches his third year in prison this September. Under Iranian law, criminal offenders become eligible for clemency or parole upon completing one-third of their sentences.