Hamas must halt its campaign of summary executions of suspected collaborators, Amnesty International today said after at least 18 more Palestinians were put to death by firing squad for allegedly providing information to Israel.It brings the number of alleged informants executed in the past two days to 21, including several people arrested yesterday in relation to the killing of three senior Hamas commanders by Israeli forces.“This flurry of executions by Hamas is made even more shocking by the fact that the victims were sentenced to death after trials which, if they happened at all, were summary and grossly unfair,” said Anne FitzGerald, Amnesty International’s Director of Research and Crisis Response.“Hamas must immediately and totally cease its use of the death penalty.”At least 11 people, including two women, were executed by firing squad today in al-Katiba prison yard in the west of Gaza City.Seven others were executed after Friday prayers outside the main mosque in Gaza City.A piece of paper nailed to the wall of the mosque said they provided the enemy with information about tunnels, houses and locations where rockets were held, which were then bombed causing the death of many Hamas fighters.“As a result the judgment of the revolutionary court was implemented,” the note read.The identities of those executed is not yet known as the victims had their heads covered. Their executioners in the firing squad were also masked.The Hamas-run website Al Rai warned that "the same punishment will be imposed soon on others". Treason is a capital offence under Palestinian law.Under Palestinian law, all death sentences must be ratified by the Palestinian Authority President, Mahmoud Abbas, but the Hamas administration carries out executions without obtaining the president's approval.“To put people to death following summary and grossly unfair proceedings is clearly cruel and inhumane. Hamas must also remember that the right to a fair trial before a competent court remains in force during times of armed conflict,” said Anne FitzGerald.Israel killed three Hamas military commanders in an airstrike on a house in the southern Gaza Strip on Thursday, an attack which also left seven of the men’s family members and neighbours dead.