Hamas militants in the Gaza Strip have executed 18 Palestinians accused of collaborating with Israel.

Witnesses say that in one incident, the militants lined up seven men outside a mosque in one of Gaza's main squares. The gunmen shot the suspects, whose heads were covered by bags, in front of hundreds of people.

A note posted on a nearby wall said the men had leaked information about the location of tunnels, fighters and weapons that were later struck by Israel.

The executions took place one day after Israel killed three top Hamas military commanders.

Also Friday, Hamas claimed responsibility for kidnapping and killing three Israeli teenagers in June - the incident that led to the current war in Gaza.

Hamas leader Saleh Arouri told a conference in Turkey that Hamas' military wing carried out the operation with the goal of starting an uprising.

Speaking in Arabic at the International Union for Muslim Scholars in Istanbul, Arouri said Hamas aimed to "ignite an intifada" by Palestinians in the West Bank and Jerusalem. He said that effort "reached a peak in the heroic operation that the Al-Qassam Brigades carried out by capturing the three settlers in Hebron."



Al-Qassam Brigades is Hamas' military wing. Until Arouri's comments Friday, Hamas had not said directly that it staged the kidnapping and killing of the three young Israelis.

In Israel, government spokesman Mark Regev said the Hamas leader has shown his group has "no qualms whatsoever about targeting innocent civilians."

In fighting Friday, Palestinian officials say Israeli airstrikes Friday killed at least four Palestinians and wounded at least 40 others.

Israeli officials say a 4-year-old boy was killed after a mortar hit near a kindergarten in southern Israel. They say he is the first Israeli child to die from the violence that started July 8.

An Israeli defense spokesman, Peter Lerner, said the mortar in that attack was fired from a site next to a Hamas-run shelter for displaced people. The Israeli military had earlier said the site was next to a U.N. school and said it had sent a protest to the U.N. refugee agency, UNRWA.

Israeli Prime Minister Benjamin Netanyahu has vowed Hamas will "pay a heavy price" for the attack on the Israeli child. The U.S. ambassador to Israel, Dan Shapiro condemned what he called the "outrageous terrorist attack" in strongest terms.

In another development Friday, Palestinian President Mahmoud Abbas and exiled Hamas leader Khaled Meshaal held a second day of talks in Qatar to "follow up" on Thursday's three-hour meeting. Qatar's emir Sheikh Tamin bin Hamad al-Thani hosted the discussion.