Islamic Hamas movement on Monday warned Israel against chasing down Palestinian prisoners who were freed by Israel in exchange for Israeli soldier Gilad Shalit.

"The Israeli threats against the freed prisoners express a state terrorism," said Ismail Al-Ashqar, a Hamas official in Gaza.

Israel "must realize that the Palestinian resistance, which got the prisoners out, will not stand idly by if those prisoners were targeted or harmed," he added.

Al-Ashqar was referring to hundreds of prisoners who were freed last year in a prison swap deal between Israel and Hamas, under which Hamas also freed the Israeli soldier after keeping him in captivity for five years.

The Israeli army said on its website that it follows up the prisoners, especially those in the West Bank, and that some of them returned to conduct "terrorist activities."

The army said intelligence information was successful in preventing "terror activities" and dealing with the recently released Palestinians. "The true challenge is monitoring terrorists who were deported overseas and manage to work for terror organizations in an indirect manner," the army said, referring to about 200 prisoners who were expelled to Gaza or outside the Palestinian territories.

Among the prominent figures released as part of the Shalit deal is Hana Shalabi, an activist of the Islamic Jihad from the Jenin area. Shalabi was arrested after Israel found "credible intelligence revealing that she was in preparation to carry out complex terrorist attacks against military targets and the home front," according to the Israeli army.

Shalabi was released and transferred to Gaza following her hunger strike in the Israeli jail. She will stay in Gaza for three years.