Palestinians across the West Bank and Gaza Strip were on Tuesday to mark Prisoners' Day in solidarity with the thousands of Palestinians in Israeli jails.

Throughout the day, Palestinians will attend marches and rallies in all the main towns and cities to remember 4,700 prisoners being held by Israel.

This year's Prisoners' Day is likely to be remembered as symbolic as it is also the day when Israel will release Khader Adnan, an Islamic Jihad prisoner who went on hunger strike for a record 66 days in protest at being held without charge.

Adnan, whose nearly 10-week fast turned him into a national hero, will be freed outside Ofer prison near the West Bank city of Ramallah at 1300 GMT, his family said.

It is also the day when 1,600 Palestinian prisoners are to begin an open-ended hunger strike, Prisoners Minister Issa Qaraqaa told AFP this week.

The main event in the West Bank will take place in central Ramallah from midday (0900 GMT) after which demonstrators will stage a sit-in outside Ofer prison ahead of Adnan's release.

In Gaza, the main march will begin at 10:30 am (0730 GMT) from central Gaza City.

Events to mark the day began on Monday evening when around 4,000 people gathered in Arraba, Adnan's home village.

"The celebrations on Prisoners' Day are different this year because the conditions of Palestinians detained in Israeli prisons have worsened," Qaraqaa told the flag-waving crowds as he unveiled a huge memorial fresco.

"There will not be peace in the region without the liberation of all Palestinian prisoners," he said.

Of the Palestinians currently detained, some 320 are being held under administrative detention orders, whereby they are held without charge for renewable six-month periods, the prisoners' ministry says.