The Archbishop of York has pleaded for an end to "depraved and unconscionable" action by the state of Israel.
It comes as fellow international church leaders returned from a visit to the bombed Holy Family Church in Gaza, describing the scenes of starvation as "humiliating".
In a statement, Most Rev Stephen Cottrell said: "I cry out against this barbaric assault on human life and dignity. It is a stain on the conscience of the international community, and a flagrant breach of international humanitarian law."
This week, Britain joined 27 countries in condemning Netanyahu's denial of aid to the region, which Cottrell described as "an important – if long overdue – sign of growing international resolve to end this war."
"There is no time to wait," he said. "There are no excuses for the bombing of places of worship where desperate people are taking shelter, or hospitals where the sick and injured are being cared for. I echo the words of Pope Leo XIV and say clearly that this barbarism must stop."
The Archbishop also condemned the pain of the 7th October attacks, saying: "With my sister and brother bishops in the Church of England, I have condemned many times the horrific Hamas attacks... I continue to call for the release of those still cruelly held hostage."
However, he emphasised that he believes Israel's actions have surpassed self-defense, saying: "This war is now one of aggression – it is a grave sin and it must stop."
Most Rev Stephen Cottrell closed by urging prayer: "I encourage dioceses and parishes to continue praying for our Palestinian Anglican sisters and brothers and all other Christian communities – and for security, freedom and dignity for Palestinians, Israelis and all the peoples of the region."