Meanwhile, the Syrian government forces, which receive air support from Russian Federation, are pushing against the extremists in the countryside south of the city. Moscow backs the Syrian government, which also is aided by Iran and Lebanon's Hezbollah as it claws back territory from Syrian rebels and Islamic State of Iraq and the Levant (ISIL) militants. "So the civilian casualties are large", Egeland added.
On Tuesday, more than 40 people were reportedly killed in a single incident when a coalition airstrike allegedly struck a residential building near the city's amusement park, citizen journalist group Raqqa is Being Slaughtered Silently reported via messaging app Telegram.
The intensity of the bombing campaign, combined with the Islamic State's stranglehold on Internet access in Raqqa, has made monitoring the situation on the ground more challenging than at any time during the Syrian war. As a result it was named the group's de-facto capital in the Middle East.
US-backed forces claim to have retaken the clock tower in the centre of Raqqa that was the site of Islamic State's first public murders and, later, the place where the British jihadist Mohammed Emwazi died.
The SDF is believed to have captured more than half the city.
The child, who identifies himself as Yousef and is thought to be aged 10, says to the camera: "My message to Trump, the puppet of the Jews: Allah promised us victory, promised you defeat".
According to reports UNICEF is receiving from inside Raqqa city, several thousand children continue to be trapped - caught in the direct line of fire. USA officials told Reuters that there now are about 10 to 12 calls a day on the hotline, helping keep US and Russian warplanes apart as they support different fighters on the ground.
"The Syrian government calls on the Security Council to implement resolutions pertaining to the fight against terrorism, especially Resolution 2253 that covers asset freeze, travel ban, arms embargo and listing criteria for Daesh, al-Qaeda plus associated individuals and groups, and to immediately stop the coalition's crimes against innocent Syrian civilians", they read. It came out one day after the terror group published photos online of a purported suicide bomber in Iraq, who appeared to be in his early teens, if not younger.
"We're not the flawless guys", United States Defense Secretary Jim Mattis told reporters in Baghdad on Tuesday.
Asked about an increase in civilian casualties resulting from USA airstrikes around the ISIS stronghold of Raqqa, Defense Secretary James Mattis said Tuesday no military in world history has been more careful that the US -led coalition in limiting civilian casualties, but it is fighting an enemy that hides behind innocent people including women and children. "More can and must be done to preserve the lives of civilians trapped in the conflict and to facilitate their safe passage away from the battleground".