The sources who spoke on condition of anonymity expected that the assassinations might be carried out against political activists as well as militants of Islamic Jihad (holy war) and Fatah armed wings al-Aqsa Brigades and Abu el-Reesh Brigades.
Israel described the targetted killing of Palestinian militants and political leaders as defusing ticking bombs.
The sources said that the focus would be on the three groups after they had carried out a series of attacks in the Gaza Strip and the West Bank, killing one settler and an Israeli soldier in the past two days.
Meanwhile, Israel radio reported that instructions were issued to the Israeli army to carry out an expand army operation against Islamic Jihad, al-Aqsa Brigades and Abu el-Reesh Brigades.
The Israeli army plans to step up operations against Islamic Jihad in the West Bank, and particularly the Jihad networks based in Tulkarem and Jenin where it had arrested at least 50 members since Monday.