Humanitarian efforts in Aleppo have been suspended in protest against the lack of action from the international community to stop the unfolding massacre in the Syrian city.

The move, supported by a coalition of Syrian civil society organisations, comes as the UN reported civilians are being shot on the spot by pro-government forces entering homes in eastern Aleppo.

Multiple sources have told the UN that at least 82 civilians had been killed by troops loyal to President Assad as the rebels’ hold on the city crumbles.

Tens of thousands more remain trapped in the city without access to food, water, medical facilities or staff.

In a “message to the world”, the humanitarian organisations said: “In response to the atrocities committed by the regime against our people in Aleppo, and in Syria generally, we – Syrian civil society organisations – declare that we are suspending our operations in an outcry against the international community’s complicity in this massacre.

“This suspension will only be revoked if concrete and meaningful measures are taken to stop the regime violence, ensure protection of civilians, and facilitate their safe and dignified evacuation.

“In effect, the regime is besieging around 50,000 civilians in eastern Aleppo and is practicing forms of systematic violence such as the use of bunker buster bombs and summary executions, without discrimination between women, men and children.”

The message has been publicised by Christian Aid, which is calling for the UK government to step up diplomatic engagement to end the conflict and prevent the deaths of even more civilians.

Earlier this week, a worker for one of the charity’s partner organisations in the city was killed by shellfire.

Máiréad Collins, advocacy and programme officer for Syria at Christian Aid, said: “What we are witnessing in Aleppo right now is horrifying. We are seeing the massacre of innocent men, women and children in their homes and on the streets, while the world watches in a state of paralysis.

“We are witnessing the unravelling of humanity before our eyes. People are posting their final goodbyes on social media, expecting that they will now be killed by regime forces. This is unbearable.

“Christian Aid, like thousands of other NGOs and civil society organisations, call again for an immediate ceasefire and humanitarian access to civilians in besieged areas.”

Christian Aid is working with local organisations in Syria, and in Lebanon and Iraq, to provide vital assistance to thousands of families displaced by the crisis.

The charity is supporting especially vulnerable refugees, such as women and people with disabilities, to access much needed services.

To find out more, or to donate, visit the Christian Aid Syria Appeal webpage.