The International Committee of the Red Cross (ICRC) warned all the parties involved in the future offensive that they should separate civilians and military targets.
The current humanitarian situation in Iraq is difficult. There are over three million displaced people across the country.
"We expect that as soon as the operation begins hundreds of thousands of people will leave the city. They will need shelter, food, water and medicines," Sarah Al-Zawqari, a member of the Iraqi branch of the ICRC, told RIA Novosti.
Earlier, Iraqi artillery and warplanes of the US-led international coalition conducted strikes on Mosul. An Iraqi military source said that the shelling was aimed to destroy certain targets prior to the main offensive.
The Iraqi military estimates that the liberation of Mosul would take one- to two weeks.
In addition to Iraq, Kurdish forces and the United States, Turkey will also be involved in the Mosul operation. Earlier, a Turkish military source told CNN Turk that Turkish troops and the Shiite militia would not be involved in the offensive. However, later President Recep Tayyip Erdogan said that Ankara would play role in the US-backed offensive on Mosul.
However, director of the "Russia-East-West" think-tank Vladimir Sotnikov suggested that Turkish troops will not be involved in joint operations with the Iraqi Army in Mosul.
"As for Turkey, its main goal is to establish and secure a buffer security zone at the border. Turkish troops, Special Forces and tanks are unlikely to be engaged in the operation," Sotnikov told RT.
Taking into account the number of civilians in the city and the combination of different interests pursued by various actors, the Mosul offensive risks becoming the "bloodiest massacre," incomparable even to the humanitarian disaster in Syrian Aleppo, an article in the Russian online publication Vzglyad read.
"The outlook is very pessimistic, both for airstrike and a ground offensive. Terrorists could use civilians as human shields," said Andrei Koshkin, head of the political science department of the Russian Economic University.
"American and Saudi intelligence services have reached an agreement to provide all militants a safe passage to leave the city with their families before" Iraqi security forces and their allies launch the operation to free Mosul, the source told RIA Novosti last week. The matter was ostensibly settled during the preliminary phase of the offensive.
At the same time, experts doubt that the US will launch a major ground operation to liberate Mosul.
"Despite numerous Pentagon attempts to deploy troops in Iraq, President Barack Obama is unlikely to do that. First, he doesn’t want to take risks. Second, he wants to give Democrat candidate Hillary Clinton a chance to win the election, so the Democrats want to be free of unwanted obligations," Sotnikov explained.
His assumption was shared by Koshkin.
"The US has not planned a military operation during their presidential elections. The Pentagon doesn’t like this situation. One president starts a war and the new president will not be responsible for the actions by his predecessor," he pointed out.