ALEPPO, SYRIA: A convoy delivering aid to Syrians in Aleppo province was hit by a deadly air strike hours after the Syrian military declared an end to a week-long ceasefire, with an outraged UN warning it could amount to a war crime.

The UN said at least 18 trucks in the 31-vehicle convoy were destroyed late Monday en route to deliver humanitarian assistance to the hard-to-reach town of Orum al-Kubra.

The Syrian Observatory for Human Rights said 12 Red Crescent volunteers and drivers had died in the strike while UN aid chief Stephen O’Brien said initial reports indicated “many people” were killed or seriously wounded.

“Let me be clear: if this callous attack is found to be a deliberate targeting of humanitarians, it would amount to a war crime,” O’Brien said.

The Observatory was unable to confirm if the planes responsible were Syrian or Russian.

The UN and Syrian Arab Red Crescent humanitarian mission had sought to take advantage of the ceasefire, which collapsed on Monday night as shells and bombs rained down on Aleppo city and the surrounding province.

Damaged Red Cross and Red Crescent medical supplies lie inside a warehouse after an airstrike on the rebel held Urm al-Kubra town, western Aleppo city, Syria September 20, 2016. REUTERS/Ammar Abdullah

The Observatory said a total of 36 people had died in the violence across the battleground region.

Syria’s military announced the end to the truce earlier Monday, accusing rebels of more than 300 violations and failing to “commit to a single element” of the US-Russia deal.

The ceasefire, which came into force on September 12, saw an initial drop in fighting but violence began to escalate late last week and the deal came under severe strain over the weekend.

US Secretary of State John Kerry had warned that the truce could be the “last chance” to save the country.

The attack on the convoy is likely to provoke anger at the UN General Assembly in New York, with the delivery of aid to desperate Syrian civilians in rebel-held areas stressed as a key condition of the deal by Washington.

The US, Russia and other key players are set to gather there on Tuesday for talks aimed at ending the five-year conflict that has killed more than 300,000 people and displaced millions.


Air raids, shelling after truce

Air strikes and shelling pounded multiple battlefronts in Syria into the early hours of Tuesday after the army declared a fraught week-long ceasefire over.

In battleground second city Aleppo, air raids and artillery fire hit rebel-held districts until approximately 2:00 am (2300 GMT Monday).

Residents spent the night huddled together in their apartments, sharing news about the collapsing truce by messenger.  On Tuesday morning, loud booms were heard intermittently across the city.

Aleppo – like other major front lines in Syria – had been relatively calm for the first few days after the truce brokered by Moscow and Washington came into effect on September 12.

Violence slowly escalated late last week, culminating at the weekend in deadly air strikes on Aleppo and a US-led raid that killed scores of Syrian soldiers fighting the Islamic State group in the east.

Fighting also intensified in the rebel-held eastern suburbs of Damascus, where the army announced a major military operation on Monday just hours before declaring the ceasefire over.

Artillery fire also hit the rebel-held central town of Talbisseh, activist Hassaan Abu Nuh said.

In the north-western province of Idlib, activist Nayef Mustafa said that planes had circled over the town of Salqin, which is held by Syria’s former Al-Qaeda affiliate in alliance with Islamist rebels.

“It’s calm now, but there was machinegun fire by military aircraft overnight,” Mustafa said.

“The ceasefire has collapsed and people are getting ready to be hit by barrel bombs. This is our situation.”

The US-Russia truce deal had been billed as the best chance to put an end to more than five years of conflict, in which more than 300,000 people have been killed.

The army declared an end to its ceasefire on Monday evening.