The Palestinian resistance group said on Friday it would return to its strategy of kidnapping soldiers if thousands of Palestinians remain locked up in Israeli jails.
Hamas, which along with other resistance organisations agreed to a three-month ceasefire in its struggle with Israel, has made their release a key condition for the truce to succeed.
"We are asking the Palestinian Authority to work for a release of all prisoners from all groups," Nizar Nayyan, a senior official of Hamas told a demonstration in the Gaza Strip.
"If the prisoners are released during the truce, good. If not, we will kidnap Jewish soldiers until the release of the last Palestinian held in an Israeli jail," he added.
The demonstration organised by Hamas after Friday prayers was attended by all Palestinian groups as well as around 50 women whose sons or husbands are in Israeli jails.
Palestinian officials say Israel still holds 8,000 Palestinians, including children, arrested since an uprising for independence began in September 2000.
Israel puts the figure at 5,900 and says it has released more than 50 prisoners since the latest truce.
Israel has also said it will not release any members of Hamas or Islamic Jihad.
Abbas' tough position
To analysts, Friday's demonstration is a further evidence of the difficult position that Palestinian Prime Minister Mahmoud Abbas is in.
"Abu Mazen (nom de guerre) is facing mission impossible," Mahdi Abd al-Hadi, head of the Palestinian Academic Society for the Study of International Affairs, said.
"The truce is very fragile if he (Abbas) cannot deliver their demands, to stop the bleeding and to release the prisoners."
But Ali al-Jerbawi, of Bir Zeit University in the West Bank, said the solution lay not with Abbas but with Israeli Prime Minister Ariel Sharon.
"The Palestinians deserve to feel that there is a new attitude from the Israelis ... It has to be tangible ... There should be a serious process of releasing detainees and prisoners," Jerbawi said.
Abd al-Hadi ,however, is optimistic Abbas would succeed.
"The man is learning the political game very quickly," he said. "He has realised that he is needed and that there is no immediate replacement and (if he quits) it will be chaos and the crisis will not be limited to domestic Palestinian politics."
The prisoner file was discussed by Palestinian security chief Mohammed Dahlan and Israel's Defence Minister Shaul Mofaz on Thursday evening, at the Erez crossing at the edge of the Gaza Strip.
"The Palestinian position is still that we are asking for the release of all our prisoners," Dahlan said.
The security chiefs also discussed Israeli withdrawals from Palestinian villages.
The two issues will be raised again by Palestinian Prime Minister Mahmoud Abbas and his Israeli counterpart Ariel Sharon, who, according to officials, are due to meet next week.
Israeli forces pulled back from areas in Gaza and the West Bank city of Bethlehem last week, under the "road map" peace plan that calls for a Palestinian state by 2005.
A group of foreign peace activists and local residents managed to re-open a road east of the northern West Bank city of Jenin on Friday.
The road has been closed since the start of the intifada.