“Arms transfers should not occur where there is a real risk that they will be used in the commission of crimes against humanity, violations of international humanitarian law, or war crimes. In Syria, this is a tragic reality,” Paulo Pinheiro, the chairman of the International Commission of Inquiry on Syria said as he introduced the report to the Human Rights Council.

He noted that failure to bring about a settlement to the conflict has led it to deepen in its intransigence and also to widen “expanding to new actors and to unimaginable crimes”.

As the fighting rages on, civilians continue to bear the brunt. In that context he noted civilians continue to face daily indiscriminate shelling and bombardment by Government forces, and that extremist anti-Government farmed groups have targeted civilians in attacks across the northern governorates.

The UN report on possible use of chemical weapons has not yet been made public, Mr. Pinheiro noted, but the latest diplomatic efforts in Geneva involving Russia and the United States aimed at removing the arsenal “may – may – form the bedrock of a broader negotiation leading to a political settlement of the conflict.”

Mr. Pinheiro, whose leads the Commission comprising of Karen AbuZayd, Carla del Ponte and Vitit Muntarbhorn, said the vast majority of the conflict’s casualties result from unlawful attacks using conventional weapons such as guns and mortars.

“The Government has continued its relentless campaign of air bombardment and artillery shelling across the country,” he said.

Since 15 July, the Commission documented unlawful attacks in 12 of the 14 governorates, with particularly intense shelling in the cities and surrounding areas of Damascus, Homs and Aleppo.

Cluster munitions continue to be dropped on civilian areas, notably in Idlib governorate, Mr. Pinheiro said highlighting some of the findings since the latest report produced by the Commission.

Those include an attack on a school in Awram al-Koubra, Aleppo countryside where the Syrian Government dropped an incendiary bomb on 26 August, according to accounts from survivors of the attack.

Eight students died in the blaze the followed with 50 others suffering fatal burns over up to 80 per cent of their bodies.

“There is no evidence of any opposition fighters or lawful targets near the school,” the Commission concluded.

Government forces have continued to launch attacks on medical personnel and hospitals, according to a separate paper, “Assault of Medical Care in Syria”.

“The discriminatory denial of the right to health as a weapon of war has been a chilling feature of this conflict,” the Commission reported, adding that the sanctity of medical care is disrespected and the sick and wounded are targeted.

Attacks on hospitals have occurred as recently as 12 September, when Government planes attacked a field hospital near Aleppo city, reportedly killing 11 people, and wounding dozens more.

Anti-Government armed groups also launched attacks on medical personnel and hospitals, the Commission established. On 16 August, fighters affiliated to Jabhat Al Nusra and Islamic State of Iraq and Al-Sham attacked a Kurdish Red Crescent ambulance in Aleppo governorate killing the driver, a patient and a paramedic.

Syria has become an increasingly dangerous place for journalists to work, Mr. Pinheiro said, noting a “disturbing pattern of harassment, arrest and detention” of journalists, especially foreigners.

In the last six weeks, reports have been received of journalists kidnapped by extremist anti-Government armed groups.

The head of the Commission also noted an “upsurge in crimes and abuses” across northern Syria committed by extremist anti-Government armed groups along with an influx of foreign fighters, in particular Al Muhajireen.

Hundreds of Kurdish civilians in northern Aleppo, Al Raqqah and Al Hasakah have been taken hostage by extremist anti-Government armed groups in connection with prisoner exchanges, according to Mr. Pinheiro.

In his statement, he also highlighted the deteriorating humanitarian conditions, particularly in the Syrian Kurdish areas, and the impact of hostilities on the socio-economic rights of Syrians.

Established by the UN Human Rights Council in 2011, the Commission is mandated to investigate and record all violations of international human rights law during the Syria conflict.

The Commission is due to make public on Wednesday its latest report based on 258 interviews and other evidence collected during the two-month period between 15 May and 15 July 2013.