The World Health Organisation has warned that the latest twist in the feud between Hamas and the Palestinian Authority is putting the lives of critically ill Gazans at risk, reports the BBC's Heather Sharp from Gaza City.

Faik Abdel-Aal rummages in drawers of baby clothes in his Gaza flat for his favourite picture of his only son. His grief-stricken wife Hanna has hidden it again.

Mohammad, who had a hole in his heart, died a week ago, aged a year and nine days. The couple are wondering who to blame.

Gaza's ailing hospitals could not treat Mohammad. His parents had already battled long and hard to arrange treatment outside the blockaded strip.

But his final days coincided with the latest power struggle between the two main Palestinian political factions threw the system for such referrals into turmoil.

Until two weeks ago, a pink-doored office in Gaza City was central to the process. It was also one of the last bastions of the West-Bank based Palestinian Authority in Gaza.

The strip is controlled by the Islamic movement Hamas, which won 2006 Palestinian legislative elections and consolidated its hold of Gaza in bloody street battles in June 2007.

After that, in protest at Hamas and its rocket fire into Israel, Israel and Egypt tightened their blockade of Gaza, virtually closing all the borders.

Complicated process

Hospitals struggled to bring in equipment and send staff out for training.

About 900 critically-ill patients per month were some of the few Gazans allowed to leave.

But to do so involved a complicated process of gathering doctors' reports, making hospital appointments, establishing financial backing from the PA, and applying for either security clearance to enter Israel or a transfer into Egypt.

Applications could take months. Human rights organisations say dozens of people have died in the past 18 months while waiting for - or after being denied - Israeli security clearance.

PA officials lead by Dr Bassam Badry handled the permit applications. But on 22 March, he says a group of Hamas men arrived at his office, ordered his staff out, and took all the patients' files.

Israel regards Hamas as a terrorist organisation and will not deal with it, so the takeover effectively closed down the main referral route.

"They have no authority," says Dr Badry. "Hamas likes to do everything by itself. But in this, I think it failed."

'Too late'

Two days after the office takeover, Faik Abdel-Aal arrived to finalise the referral for his son.

Mohammed had been deteriorating for two months, and Mr Abdel-Aal had finally secured PA funding for surgery in East Jerusalem. He just needed security clearance.

"All the papers, my son's and other people's papers were destroyed on the table. They said they would start from zero… that there was a new system in place. I was screaming and yelling because I did not have a second to spare," he said.
“ I am watching my daughter die in front of my eyes. I feel angry with the whole world. No-one is helping us ”
Mohammad al-Beik

He turned to human rights organisations, who have become the last resort for a few such cases since Hamas took over. A transfer was eventually arranged, a day later than planned. But by the time Mohammad arrived, it was too late. He died two days later.

Dr Badry reels off a list of six others who have also died since Hamas took his office, among them heart and cancer patients and a burns victims.

He believes his staff could have saved them, but this is impossible to confirm.

Even if the permit applications had gone ahead as usual, it might already have been too late, or Israel could have denied security clearance.

And there is also the decision by the Palestinian Authority to cut down the number of patients it funds for treatment in Israeli hospitals, rather than West Bank , Jordanian or Egyptian facilities.

The Abdel-Aal family also had trouble with the rescheduling of an appointment in East Jerusalem , but say they had no financial backing to try an Israeli hospital.

The same issues also hang heavy over Fatima and Mohammad al-Beik, as they wait by a hunched figure in a wheelchair outside Gaza's Shifa hospital.

The doctors in Gaza say cancer is spreading in her lungs and stomach, but they are not equipped to give her the chemotherapy she needs.

Mr Beik has been told Mona has PA funding for treatment in Jordan. But the border with Egypt is currently closed, and to go through Israel she needs Dr Badry's office to arrange security clearance.

But even if that was sorted out, the funding covers only Jordan - and Mr Beik says getting a visa could take a month.

"I am watching my daughter die in front of my eyes. I feel angry with the whole world. No-one is helping us," says Mr Beik.

'Corrupt system'

Dr Hassan Khalaf, deputy health minister in the Hamas-run administration, says the the old process was corrupt and badly managed - accusations the PA denies.

"It wasn't a proper system," he says, adding that the PA officials "refused to co-operate with us".

He points out that patients have died waiting for Israeli clearance anyway. "Where were human rights organisations to blame Israel for that? Why is Israel free to kill, but it is forbidden for us to say we should be fair and we should be honest?"

He says the takeover was done "peacefully with full respect" and Hamas is working on a new system under which 12 patients have so far been transferred to Israel through co-operation with Israeli human rights groups.

Dr Khalaf is also critical of the PA decision to reduce referrals to Israel.

The PA says its reason is to save money and invest in West Bank hospitals, and that care can still be arranged in Israel as a last resort.

But Dr Badry says it was a "political decision because of the war on Gaza". He admits it has made things harder for some Gazan patients. "But it is an order," he says flatly.

Mediators are working for some kind of compromise between the two factions as broader Palestinian unity talks rumble on with little tangible progress.

In the meantime, a man lay motionless with a brain haemorrhage in Shifa hospital; another was propped up in bed, bandages swathed over severe burns.

The doctors said the two men need care outside Gaza . I have since heard that they both died.