NEW DELHI: Fighting in Aleppo has intensified after a fragile ceasefire brokered by Russia and the United States in Syria collapsed last week and the Syrian government stepped up strikes on rebel-held areas of the city. The situation has prompted the United Nations Security Council members, namely the US, the UK and France, to call for a special meeting, that is expected to take place today.

As reports emerge of the raging battle, with Aleppo once again being the scene of some of the most intense fighting, United Nations Secretary-General Ban Ki-moon called it a “dark day” for the global commitment to protect civilians, and stressed that the use of 'bunker buster' bombs and other indiscriminate weapons in densely populated areas may amount to war crimes.

“The Secretary-General is appalled by the chilling military escalation in the city of Aleppo, which is facing the most sustained and intense bombardment since the start of the Syrian conflict,” said a statement issued by Ban’s spokesperson in New York.

Since the announcement two days ago by the Syrian Army of an offensive to capture eastern Aleppo, there have been repeated reports of airstrikes involving the use of incendiary weapons and advanced munitions such as bunker buster bombs, according the statement.

“The Secretary-General underlines that the apparent systematic use of these types of indiscriminate weapons in densely populated areas may amount to war crimes,” it added.

Emphasizing that the UN chief considers this a “dark day” for the global commitment to protect civilians, statements says the international community has to unite to send a clear message that it will not tolerate the use of indiscriminate and ever-more deadly and powerful weapons against civilians.

Ban's call comes just days after a ministerial level meeting of the UN Security Council on the situation in Syria, where he said the five-year conflict, which has killed some 300,000 people, is at “a make or break moment,” and challenged the Council to use its influence “now to restore a cessation of hostilities, enable humanitarian assistance everywhere it is needed, and support the United Nations in charting a political path for the Syrians to negotiate a way out of the hell in which they are trapped.”

The escalation followed a landmark ceasefire that was implemented in parts of Syria, but broke down last week. The ceasefire had been called in order to deliver much needed aid and assistance to people trapped in areas affected by the fighting -- with Aleppo being one of the areas worst affected.

The UN says the attacks on Aleppo have left nearly two million people without water. Further, UNICEF -- the children’s arm of the UN -- said that fierce air strikes on Friday stopped repairs to a damaged water pumping station supplying rebel-held eastern districts of Aleppo. It added that a nearby station pumping water to the west of Aleppo has been switched off. The situation prompted Unicef spokesperson Kieran Dwyer to say that water was being used as a tool of war by all sides. Dwyer added that residents now had to resort to contaminated water and were at risk from waterborne diseases.

Meanwhile, fighting continues and fresh casualties were reported on Saturday. The Syrian Observatory for Human Rights said 25 people were killed in fresh bombardments. Government forces captured the rebel-held Palestinian refugee camp of Handarat as airstrikes pounded rebel-held eastern neighborhoods of Aleppo, killing 52 people, including 11 children and six women, SOHR said. The Local Coordination Committees, another monitoring group, said 49 were killed on Saturday alone.

SOHR added that the death toll in Aleppo is expected to rise since many people are in critical condition and rescue workers are still digging through the rubble.

Reports from the ground contend that the latest bombings are the worst that they have seen, with photos and videos emerging from the scenes corroborating the above.