The situation in the eastern part of Aleppo is still grim after a ceasefire to allow the evacuation of opposition fighters and tens of thousands of civilians is on the verge of collapse.

Shelling has resumed in the rebel part of the city and buses meant to be used in the evacuation have returned to their depots, according to Syrian activists.

It comes after trapped residents and activists took to Twitter to send heartbreaking "goodbye" messages as the Syrian government's forces closed in.

The UN's human rights office said Syrian pro-government forces have been entering homes in eastern Aleppo and killing civilians inside, including women and children.

People reacted to the reported massacre by sharing on Instagram minimalist cartoons with the Arabic name for Aleppo and blood dripping from the letters:

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Others shared variations of the cartoon, with the final letter -- a 'P'-- which becomes an eyelash crying blood:

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Or the famous 'Girl with a balloon' by Banksy:

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The Associated Press contributed reporting.

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