Israel still holds 423 Palestinian children aged under 18, the Palestinian Center for Defending Prisoners said on Monday.

"The children stay in very difficult circumstances in the Israeli jails," the center said in a report, adding the Israeli jailers "put them under psychological pressure and some jailers molested some of the children."

The prison authorities places eight to ten children in one room of four meter square, the report added.

According to the center, "231 of the children were sentenced while 182 are still waiting their trial. Ten children are subject to administrative detention without any charge."

In 2006, Islamic Hamas movement captured an Israeli soldier in a cross-border raid near the Gaza Strip and demanded to exchange him for a number of Palestinian prisoners.

Hamas still holds the Israeli soldier and Egyptian-mediated talks to achieve a swap collided with Hamas' insistence to select the names of the first 450 prisoners and Israel's rejection.

In addition to the 450, Hamas stresses that Israel must also free all the children, women, old prisoners and leaders of the Palestinian groups.