Tabqa

International humanitarian organizations have ceased operations and have evacuated all associates in northeast Syria after the start of the Turkish military operation. Humanitarian aid supplies have also been cut off, according to the self-proclaimed Kurdish Autonomous Territory, quoted by RIA Novosti.

The BBC has uncovered details of a secret deal that let hundreds of IS fighters and their families escape from Raqqa, under the gaze of the US and British-led coalition and Kurdish-led forces who control the city.

Russia on June 19 warned it would track U.S.-led coalition aircraft in central Syria as "targets" and halted an incident-prevention hotline with Washington after U.S.forces downed a Syrian jet.

Moscow has only once before suspended the hotline, which was established in October 2015 to prevent conflict between the different forces operating in Syrian airspace.

The United States on Tuesday began providing small arms to Kurdish fighters battling the Islamic State group in northern Syria, the Pentagon said, fulfilling a pledge that has infuriated Turkey.

The weapons transfers have begun ahead of an upcoming offensive to recapture Raqqa, the last major bastion for IS in Syria.

A US-backed alliance of Arabs and Kurds will launch their final assault on the Islamic State group's Syrian bastion Raqqa in early summer, a commander said on Friday, AFP reported.

"The attack on Raqa will take place in the beginning of the summer," Syrian Democratic Forces commander Rojda Felat told AFP without giving a more precise date.

Forces such as Apache helicopters, U.S. Marine artillery and special operation troops were part of a U.S.-led coalition operation to air drop Syrian militia into an area near the Islamic State of Iraq and the Levant's (ISIL) stronghold Raqqa, a U.S. official said on March 22. 

The U.S.-led coalition has airlifted Syrian rebel forces to an operation near the Syrian town of Tabqa in Raqqa province while providing them with fire support, U.S. defense officials said on March 22.

At least 31 Islamic State militants were killed in Syrian air force raids Sunday in the northern province of Raqa, a stronghold of the jihadist fighters, a monitoring group said.