Israeli defence sources have warned that the government decision to release 199 Palestinian prisoners as a gesture to the Palestinian Authority - and to apply pressure on Hamas over the negotiations to free Sergeant Gilad Shalit - might backfire.

A special ministerial committee, headed by Prime Minister Ehud Olmert, decided on the release on Monday and approved a list of 199 long-serving prisoners prepared by the Justice Ministry and the Shin Bet intelligence agency. Two of the prisoners, serving life sentences, participated in the murder of Israelis almost three decades ago, and many of the others were involved in planning murders. The prisoners are to be released by the end of this month, before the beginning of the Muslim month of Ramadan.

Palestinian women hold photos of their jailed relatives at a protest

The decision to release a large number of "senior" prisoners was reached after repeated requests by Palestinian President Mahmoud Abbas and the urging of the US administration to strengthen the moderate camp in its power struggle against Hamas. Most of the prisoners on the list are Fatah members and none of them is affiliated with Hamas or Islamic Jihad. While not saying so officially, the intention is also to create pressure on Hamas within the Palestinian public where the incarceration of 9,000 prisoners is a crucial issue.

Egyptian-brokered talks to secure the release of Sergeant Shalit, captured more than two years ago, have foundered over Hamas demands for the release of over 800 prisoners, including many convicted murderers.

The hope is that now that Hizbollah and Fatah have both managed to release their prisoners, Hamas will also be forced to deliver.

"This will increase the pressure on Hamas," a defence source told the JC, "but it will also push them to show that they can do better, get more prisoners with blood on their hands in return for Gilad. So it might actually backfire."

Transport Minister Shaul Mofaz and Internal Security Minister, Avi Dichter, both candidates in the Kadima leadership primaries voted against the release. Organisations representing the families of terror victims also criticised the decision, and promised to protest to the Supreme Court.