The formation of a Palestinian unity government faced a last-minute hitch on Monday, jeopardising a long-awaited reconciliation deal between President Mahmoud Abbas and the Islamist group Hamas.
Abbas was due to swear in the new administration later in the day in a ceremony that Palestinians hoped would mark the end of years of quarrelling between Hamas, which governs Gaza, and secular nationalist parties that hold sway in the West Bank.
However, Hamas has announced that it will not support the government because of a decision by Abbas to scrap the Ministry for Prisoner Affairs and replace it with a committee that will fall outside the control of the cabinet.
The prisoners' minister deals with Palestinians held in Israeli jails. Palestinians view the detainees as freedom fighters while Israel denounces them as terrorists.
"No, and a thousand times no. How could we possibly abandon those who have spent most of their life (in prison) for the sake of God?" Hamas Interior Minister Fathy Hammad told a gathering in Gaza that had been expected to celebrate the new government.
Officials close to Abbas said that the new administration, made up of technocrats and academics whose names had previously been approved by Hamas, would be sworn in at 1.00 p.m. (1000 GMT) regardless of the latest row.
Hamas said it would not recognise such a body, meaning the unity deal would be in tatters from the word go.
A Palestinian official said Abbas wanted to close the ministry to secure continued Western funds for the government, with some international donors warning they would not support an administration that finances Palestinians jailed in Israel.
The Palestinian government pays monthly salaries to the families of the prisoners. Israel says this encourages attacks against its security forces and civilians, and has condemned donors whose aid helps cover such handouts.
Israel has urged the United States and Europe to shun any unity government supported by Hamas, which does not recognise Israel's right to exist and has not renounced violence, regardless of whether the prisoners' ministry survives.