Official says twins had been in poor health since birth this week, and lack of experience among staff contributed to decline

A rare moment of brightness in the grim reality of life in Gaza came to a premature end on Thursday with the death of twin three-day-old lion cubs at an amusement park.

No explanation was given for the cubs' demise in announcements on local news websites a day after endearing images of the pair were published on news websites around the world. But an interior ministry official told the Guardian that the cubs had been in poor health since birth, had not been feeding well and their father had been aggressive towards them.

The lack of experience among zoo staff in caring for exotic animals had contributed to their decline, he added. Officials had made contact with a zoo in neighbouring Egypt to request advice and specialist food and equipment, but nothing could be brought into Gaza because of the continued closure of the crossing, he said.

Saud Shawa, a veterinarian in Gaza, said he was saddened by the news but he had expected it. There was no resident vet at the Bissan amusement park – a Hamas-run establishment in northern Gaza where the cubs were born – and no one with adequate experience of dealing with lions, he said.

"Lions are very sensitive and our atmosphere is not suitable. They need specialist care by qualified zookeepers," said Shawa, one of around 70 vets in Gaza. He suggested that the cubs may have become cold or their feeding regime may have been unsuitable.

The twins were given names to mark the anniversary of last year's eight-day conflict between Gaza and Israel, which ended a year ago on Thursday. The male cub was called Fajr, after rockets fired across the border, and his sister was called Sijil, the name Hamas assigned to the conflict.

The cubs' parents were smuggled into Gaza four years ago through tunnels underneath the border with Egypt. Since Israel imposed a strict blockade on Gaza in 2007 – since eased – the strip's five zoos have been stocked with exotic animals brought through the tunnels.

The issue of animal rights does not have high priority in Gaza. Life for its zoo animals is one of hardship. At the South Forest park in Khan Younis, living animals are confined in small cages alongside their stuffed dead comrades. A zoo in Gaza City painted stripes on a donkey to pass it off as a zebra after two real zebras died.