The archbishop of Westminster said he was deeply shocked by his first visit to Gaza on Sunday, and that he had seen “a deeply depressing situation in a devastated region where people are trapped”.

Cardinal Vincent Nichols, the leader of the Roman Catholic church in England and Wales, toured neighbourhoods of Gaza that were virtually flattened during the 50-day war between Israel and Hamas in the summer. He visited a hospital and an industrial zone that were badly damaged by air strikes and shelling, and an orphanage caring for dozens of traumatised children, some of whom had been given up by parents unable to care for them.

“I was deeply shocked at the effects of war and endemic poverty,” he told the Guardian. “Pope Francis has said there must be an end to war, and when you see the effect in a place like Gaza it reinforces that.”

There was little sign of rubble being cleared, let alone reconstruction, he said. “It’s astonishing the number of people with the appearance of nothing to do – people just sitting on the streets. There is only the barest sense of order. This is not an economy that is going to be able to support its population.”

Nichols said he was concerned about “the innocent citizens of Gaza caught in a vice of conflicting ideologies – an almost impossible situation for them”.

The greatest fear was that the “rule of the extremists” was coming to the fore in the Middle East. “Political leaders must not be satisfied with a security or military response, but need to find a political solution,” he said.

Real political leadership was essential, he added, but “optimism is not the word that comes to mind, yet without it things will get worse.”

He had given an undertaking to the people he met in Gaza that he would try to widen public understanding of their situation, he said. Nichols has previously spoken in support of Palestinian Christians whose homes and livelihoods are threatened by a section of the vast concrete security barrier Israel is building near the West Bank town of Bethlehem.

During last summer’s war more than 2,000 Palestinians were killed in Gaza, while Israel puts its death toll at 66 soldiers and six civilians, including a Thai worker. About 17,000 homes in Gaza were destroyed and reconstruction costs have been estimated at £5bn.

• This article was amended on 24 November 2014 to clarify figures for the number of Israelis who died during the war in Gaza.

