Aleppo's devastation: The weapons of war turning city to rubble
Syrian and Russian air attacks on Aleppo have prompted accusations of war crimes and "barbarism" over claims they involve sophisticated weaponry that can have a devastating effect in residential areas.
It is not clear exactly what armaments have been deployed but UN Secretary General Ban Ki-moon cited reports of incendiary weapons and bunker buster bombs, while barrel bombs and cluster munitions have also been used previously in Syria.
Which weapons might have been used?
* Bunker busters: named for their use in penetrating hardened targets such as underground military headquarters.
* Incendiary weapons: used to start fires, including materials such as napalm and white phosphorous, which can cause severe burns if they come into contact with skin. White phosphorus has a legitimate function of generating smokescreens.
* Thermobaric bombs, also known as fuel-air explosives, set a fire that sucks the oxygen out of underground spaces and burns everything in its path.
* Cluster munitions: internationally banned weapons that release smaller submunitions, or "bomblets", over a wide area, which can lay dormant until triggered by movement.
* Barrel bombs: unguided, improvised weapons with a wide impact, often made from an oil drum filled with explosives and metal fragments and dropped from the air.
Why would they be controversial in Aleppo?
"The use of weapons in armed conflict falls under international humanitarian law, which prohibits the direct targeting of civilians and prohibits indiscriminate and disproportionate attacks," said Hannah Bryce, assistant head of International Security at the Chatham House think tank.
"The issue with many of the explosive weapons being used in Syria and in Aleppo is their use in residential areas where there is a high civilian population."
She added: "The issue however is complicated when military targets are located within civilian areas."
Bryce quoted a report by the NGO Action on Armed Violence which found that when explosive weapons are used in populated areas, 92 percent of those killed and injured are civilians.
They also often destroy critical infrastructure, such as healthcare facilities, sanitation, water and power supplies.
Ben Goodlad, the principal weapons analyst at IHS Jane's, said: "Both bunker buster and fuel-air explosive munitions are intended for use against hardened, difficult to strike targets.
"The high level of explosive and blast effects caused by these munitions would have a devastating effect on a built-up area with collateral damage being almost unavoidable."
Stephen Rapp, former US ambassador for war crimes, said "any incendiary devices are not going to be in a situation where they can distinguish between (military targets and civilians).
"They are going to cause horrible loss of life to civilians."
This article is available in French on Middle East Eye French edition.