Schools in Gaza are providing military training to teenage boys in a programme that a human rights organisation says is encouraging a culture of armed resistance and a new generation of fighters.

The school curriculum includes weekly classes in which boys are familiarised with the use of Kalashnikov assault rifles and other weapons. Instructors from the interior ministry's national security arm also teach first aid, firefighting and the values of "discipline and responsibility".

The course is supplemented with voluntary camps during school breaks, in which boys are instructed in handling guns and explosives. The Izz al-Din al-Qassam brigades, the armed wing of Hamas, the Islamist faction that governs Gaza, assist in the training, according to Gaza's ministry of education website.

It denies that real weapons are used in training. However, a video shot at the Gamal Abdel Nasser school near Gaza City appears to show students carrying Kalashnikovs and a boy firing an artillery shell at a mocked-up watchtower bearing an Israeli flag. Schoolboy Izzadine Mohammed confirmed to the Guardian that he had been trained in handling real weapons at a camp this year.

About 5,000 boys have participated in the camps since the programme started in September, according to the education ministry. The weekly classes are part of the curriculum for about 37,000 pupils aged 15-17; parents are entitled to withdraw their sons from the course, but such a move is rare.

The government is considering adapting the course for teenage girls next year. "There has been no final decision yet, we are still studying this option," said Mohammed Syam, general director of educational activities at the ministry.

He said the programme, Futuwwa, or Youth, was educational and disciplinary. "The aim is to teach students how to make decisions and take responsibility to know their commitments and obligations," he said. Activities allowed boys to release psychological pressures and learn to cope with the physical dangers of living in Gaza, he added.

There was no military training, he claimed, saying only 1% of the programme was devoted to learning about weapons. He declined to comment on the video.

Syam's comments appeared to contradict a press release issued in his name and published on the interior ministry website, saying the scheme would focus on "military exercises, particularly on weapons training and skills training in the field of military confrontation".

Mohammed, 17, said he had attended a camp for six hours a day over a two-week period at which instructors from the national security were assisted by militants from the Qassam Brigades. About 170 boys from his school were taught how to fire and maintain Kalashnikovs, as well as the use of grenades and improvised explosive devices.

"They told us the purpose was to know how to defend ourselves and how to confront the occupation," he said. "I was excited to learn how to use a Kalashnikov properly. I feel stronger and more confident."

The boys at his camp were keen to learn firefighting and first aid, "but we were happiest with the weapons training". Mohammed, whose brother, a militant, was killed by Israeli troops during the 2008-9 war in Gaza, said he was a supporter of Hamas and would consider joining the Qassam Brigades.

Al Mezan, a Gaza-based human rights organisation, criticised the programme. "It's unbelievable. Hamas has been cutting sports activities in schools for the past six years, saying there is no time in the curriculum, but now they find the time to have military training inside schools," said Samir Zakout.

"They should not be doing this. It's building a military culture, familiarising boys with resistance and creating the next generation of militants."

Syam pointed out that many other countries, in the Arab world and the west, ran military programmes for young people. In Gaza, the population had the right to armed resistance and self-defence against "the occupier", Israel, but such actions were the preserve of the military wings of political factions, he said.

The Palestinian Authority has no army, navy or air force. It has an armed police force and a number of security agencies.

Israel declared Gaza a "hostile entity" in 2007 after Hamas took control of the coastal territory. There have been two major conflicts since then, in 2008-9 and 2012, amid regular rocket fire from Gaza and Israeli air strikes.

Israeli school leavers are required to undertake military service for three years for boys and two for girls. All entrants are given combat and weapons training. Military representatives make frequent visits to schools to prepare teenagers for their army service.