Al-Aqsa Martyrs Brigades, Fatah movement's armed wing, accused Hamas security forces on Sunday of arresting 16 Fatah members in the Gaza Strip, Xinhua reported.
The group said in a leaflet that security forces with the deposed government of Hamas in Gaza had carried out a large campaign of arrests of al-Aqsa Martyrs Brigades members.
The arrests came shortly after two Hamas militants, three Palestinian security officers and one civilians were killed in armed clashes that lasted for nine hours in the West Bank city of Qalqilya.
The group warned Hamas government and its security forces that repressing Fatah members and leaders in the Gaza Strip "would oblige us to harshly respond in the West Bank against Hamas members."
Meanwhile, the two left-wing groups -- the Popular Front for the Liberation of Palestine (PFLP) and the Democratic Front for the Liberation of Palestine (DFLP) -- called on both Fatah and Hamas for restraint and to immediately form an investigation committee to stop the bloodshed.
The two groups said in a joint statement that they condemned what happened in Qalqilya, adding that they reject clamping down on militants and implementing security cooperation deals with Israel in the West Bank.
Moreover, Hamas officials said the incident in Qalqilya "would influence Hamas movement's way of dealing with Fatah movement and the Palestinian (National) Authority in the West Bank."