At least 277 civilians are reported to have died over a six-day period

The UN human rights chief is calling for urgent international action after a 'week of soaring violence and bloodshed' in Syria.

UN High Commissioner for Human Rights Zeid Ra’ad Al Hussein says the past week "has been one of the bloodiest periods of the entire conflict".

According to the UN, at least 277 civilians are reported to have been killed in the country between February 4th and 9th, with more than 800 others injured.

Recent weeks have seen a particular increase in military activity in the opposition-held Eastern Ghouta and Idlib regions.

Meanwhile, the conflict's international dimension has escalated after an Israeli fighter jet crashed after it was apparently shot down during airstrikes against "Iranian targets" in Syria.

Mr Zeid has said the continuing failure to end the war - which has been ongoing since 2011 - is an "epic failure of global diplomacy".

In a statement, he said: "The no-holds-barred nature of [the recent] assault is evidenced by reports that at least nine medical facilities, six of them in Idlib and three in Eastern Ghouta, were hit by airstrikes.

"Even by Syria’s atrocious standards, these are exceptionally deplorable developments - and a cruel irony given that both have been declared 'de-escalation areas'."

In a separate statement, UN Secretary-General António Guterres called on the parties involved in the conflict to try and find a political solution.

A spokesperson for the UN chief said: "The Secretary-General stresses once again that all concerned in Syria and the region have a responsibility and must abide by international law and relevant Security Council resolutions.

"He calls on all to work for an immediate and unconditional de-escalation of violence and exercise restraint."

Main image: Fire and smoke rise after a mortar shell launched by Syrian rebels hit an electricity generator in the Dama Rose Hotel in Damascus. Picture by: Ammar Safarjalani/Xinhua News Agency/PA Images