More than 136,000 people, including an estimated 74,000 children are trapped in the historic northern Mali city of Timbuktu, the NGO Save the Children has said.

The NGO on Monday also warned that the trapped are running out of essential items like food and medicine as armed groups block their entry into the city.

"With official aid routes completely cut off, supplies are dwindling and the agency fears the remaining services in the city may need to end soon if a resolution of the crisis isn’t found," the NGO said in a statement.

The NGO also said that it has received reports of children being maimed or killed by explosive devices, while others are recruited by armed groups.

Timbuktu, a Unesco World Heritage Site, has been under siege by al-Qaeda-linked jihadists since August.

The jihadists have banned trucks from neighbouring regions against entering Timbuktu, causing shortages and skyrocketing prices of food, fuel and other necessities.

Jihadist attacks on the city have also forced more than 33,000 people to flee, according to the UN.