The U.S. military said Wednesday it has started transferring detainees from the Islamic State group being held in northeastern Syria to secure facilities in Iraq.

The move came after Syrian government forces took control of a sprawling camp, housing thousands of mostly women and children, from the U.S.-backed Syrian Democratic Forces, or SDF, which withdrew as part of a ceasefire. Troops on Monday seized a prison in the northeastern town of Shaddadeh, where some IS detainees escaped and many were recaptured, state media reported.

Israeli forces on Wednesday killed at least 11 Palestinians in Gaza, including two 13-year-old boys, three journalists and a woman, hospitals said, on one of the war-battered enclave 's deadliest days since the ceasefire between Hamas and Israel took effect in October.

The United States is trying to push the deal forward and implement its challenging second phase.

Saudi Arabia and eight Muslim-majority countries including Gaza mediators Qatar and Turkey have agreed to join U.S. President Donald Trump's "Board of Peace", the Saudi foreign ministry said on Wednesday.

In a joint statement, Riyadh announced the "shared decision" of the foreign ministers of Saudi Arabia, Qatar, Turkey, Egypt, Jordan, Indonesia, Pakistan, and the United Arab Emirates to join the body to be chaired by Trump, saying they supported his "peace efforts" on the Gaza conflict.

Syria's defense ministry said seven soldiers were killed on Wednesday when the Kurdish-led Syrian Democratic Forces targeted an arms depot in the country's northeast, despite a fresh ceasefire announced a day earlier.

"Army forces found a factory for producing explosive devices and drone munitions" in Hasakeh province near a border crossing with Iraq, the ministry said, adding that as government forces began securing the site, the SDF "targeted it with a suicide drone, leading to an explosion and the death of seven soldiers", with 20 others wounded.

Gaza's civil defense agency said an Israeli strike in the center of the territory on Wednesday killed three journalists, including a freelancer who previously worked for AFP, despite the ceasefire between Israel and Hamas.

In a statement, the civil defense said "the bodies of the three journalists killed in an Israeli air strike in the Al-Zahra area southwest of Gaza City were transported to Al-Aqsa Martyrs Hospital in Deir al-Balah".

Recent conflict between Syrian government forces and Kurdish fighters in northeast Syria has again brought to the world's attention the detention facilities where Islamic State group members are held and camps where mostly women and children have been locked up for years.

During the battles that the Kurdish-led Syrian Democratic Forces fought against the Islamic State group over the past decade, thousands of IS fighters of different nationalities were captured and have been held in some dozen jails in northeast Syria.

U.S. President Donald Trump's government has asked countries to pay up to $1 billion for a permanent spot on his "Board of Peace" aimed at resolving conflicts, according to its charter seen by AFP.

The board was originally conceived to oversee the rebuilding of Gaza, but the charter does not appear to limit its role to the Palestinian territory.

Prime Minister Benjamin Netanyahu of Israel said Wednesday he had agreed to join U.S. President Donald Trump's Board of Peace, after his office earlier criticized makeup of the board's executive committee.

The board, chaired by Trump, was originally envisioned as a small group of world leaders overseeing the Gaza ceasefire plan. The Trump administration's ambitions have appeared to balloon into a more sprawling concept, with Trump extending invitations to dozens of nations and hinting it will soon broker global conflicts.

An Iranian Kurdish opposition party headquartered in Iraq accused Iran on Wednesday of conducting a rocket and drone attack on its premises, killing one of its members and wounding two others.

"At dawn today, the occupying Iranian state... targeted one of the Kurdistan National Army's headquarters" using missiles and drones, said the Kurdistan Freedom Party, referring to an armed group that operates under its authority.

Syria's defense ministry announced a four-day ceasefire with Kurdish forces on Tuesday, after an understanding was reached between the two sides on the future of the Kurdish-majority Hasakeh region.