On Friday masked gunmen, dressed in black, murdered seven suspected collaborators in a busy Gaza square outside a mosque. The Hamas operatives also shot 11 alleged informers for Israel at an abandoned police station outside Gaza City. It is the third time this month that Hamas has killed people suspected of leaking intelligence to Israel.

"They provided the enemy with information about the whereabouts of fighters, tunnels of resistance, bombs, houses of fighters and places of rockets," read a letter posted near the execution place.

"The occupation bombarded these areas, killing a number of fighters...Therefore, the ruling of revolutionary justice was handed upon him," the letter added.

Al Majd, a website linked to Hamas' security service, said "the resistance" had started an operation to clamp down on anyone working for the "Zionist enemy."

In a letter obtained by Reuters news agency, the Islamists said a number of other "collaborators" had surrendered to Gaza authorities.

Killings condemned

Human rights groups have denounced the executions. Sarah Leah Whitson, Middle East director at Human Rights Watch, called the killings a "horrendous abuse."

Raji al-Surani, chairman of the Palestinian Center for Human Rights, demanded that the Palestinian Authority and other groups "intervene to stop these extra-judicial executions, no matter what the reasons and motives are."

The Palestinian Center for Human Rights also urged an immediate stop to what it called "extrajudicial executions."

Attacks and counter-attacks

Meanwhile, Hamas fighters continue to fire rockets at Israel. A four-year-old boy, Daniel Tragerman, was killed in such attack on Friday, the Israeli army said.

"Hamas will pay a heavy price for this attack," Israeli Prime Minister Benjamin Netanyahu's spokesman, Ofir Gendelman, cited the Premier as saying on his Twitter account, adding that the Israeli army would "intensify ops against Hamas."

The boy was the first child to be killed on the Israeli side since the start of the Israel-Hamas conflict on July 8.

The recent escalation came three days after truce talks between Israel and Hamas collapsed in Cairo.

Palestinian medics said that an Israeli air strike hit a house in central Gaza before dawn on Saturday killing five family members, including two women and two children.

The Israeli military said it had carried out around 20 air strikes over the Gaza Strip early on Saturday and that three rockets fired by Islamists had hit southern Israel.

shs/ksb (AP, Reuters, AFP)