The death of an 11-year-old Iranian boy reportedly in an air strike while manning a security checkpoint alongside his father in Tehran has thrown focus on a new initiative to recruit children into the security services.

Alireza Jafari's mother Sadaf Monfared told the municipality-run newspaper Hamshahri that the pair had been helping Basij volunteer militia patrols and checkpoints to "maintain the security of Tehran and its people" when they were killed on 11 March.

Last week, an Islamic Revolutionary Guard Corps (IRGC) official in Tehran told the IRGC-affiliated Fars News Agency that the organisation would enrol "volunteers" aged 12 and above.

Eyewitnesses have told the BBC they have seen children, including some armed, in security roles in the capital and other cities.

Foreign-based human rights organisations have also reported Alireza's death. The Kurdish group Hengaw said he was a "fifth-grade student" who was killed while present at a checkpoint in Tehran.

Alireza's mother said her husband had told her there were not enough personnel at the checkpoint, with "only four people" present. She said he took Alireza with him and said that the boy needed to be "ready for the days ahead".

She quoted her son as saying: "Mum, either we win this war or we become martyrs. God willing, we will win, but I would like to become a martyr."

Hamshahri newspaper said they were hit by an "Israeli drone strike".

The Israel Defense Forces (IDF) told the BBC they were unable to verify this unless provided with the co-ordinates of the alleged strike.

Rahim Nadali, of the IRGC's Greater Tehran Muhammad Rasulollah Corps, said the new programme, known as Homeland Defender Fighters for Iran, would place children on various duties, including patrols and deployment at checkpoints.

Recruitment, he added, could take place at mosques attached to the Basij militia in Tehran, and in city squares where pro-establishment rallies have been held.

The Basij is a volunteer militia controlled by the IRGC, with an estimated one million members. It is often deployed on the streets to suppress dissent. Israel has said it recently targeted several Basij checkpoints.

Despite a government-imposed internet outage in Iran, the BBC has spoken to four eyewitnesses who said they had seen children under the age of 18 at checkpoints in Tehran, the nearby city of Karaj, and the northern city of Rasht.

Names have been changed for security reasons.

Golnaz, who is in her 20s in east Tehran, told the BBC that she had seen armed teenagers taking part in Basiji forces when she went out after an air strike on 9 March to see what was going on.

Sara, also in her 20s in west Tehran, told the BBC that she saw a teenager at a checkpoint on 25 March.

"He was holding a gun at the cars. He and the others were stopping cars and searching them. He was short and slight."

Last month, ordinary Iranians told the BBC about security checkpoints around the capital, where they said residents were stopped and searched.

Those who have been able to connect to the internet have told the BBC that the practice is still going on, and that some patrols go around with the Islamic Republic's flag and loudspeakers during the night.

Some have told the BBC that they have seen teenagers at checkpoints in cities other than Tehran as well.

Peyman, who is in his 20s and lives in Karaj, told the BBC that he saw what he called a "teenage boy" with a Kalashnikov at a checkpoint on 30 March. "His moustache hadn't fully grown," he said.

Tina, who is also in her 20s and comes from Rasht, told the BBC that she saw young people on duty in a square in the city on 14 March.

"They were wearing masks so their faces were covered. But it's obvious that they are children; I can see it from their eyes. They are short as well. They stand in front of those adult forces. I feel pity for them and I get scared at the same time."

In a report on the recruitment campaign, Human Rights Watch (HRW) said it was a "grave violation of children's rights and a war crime when the children are under 15".

"There is no excuse for a military recruitment drive that targets children to sign up, much less 12-year-olds," said Bill Van Esveld of HRW. "What this boils down to is that Iranian authorities are apparently willing to risk children's lives for some extra manpower."

Pegah Banihashemi, an expert in constitutional law and human rights at the University of Chicago Law School, told the BBC: "Under international law, the use of children in security or military roles is tightly constrained and, in many contexts, unlawful."

She also said that their deployment "introduces broader risks to society: untrained minors operating under pressure, often with limited command structure and insufficient understanding of force, can unintentionally escalate violence and endanger civilians".

Holly Dagres, an Iran specialist at The Washington Institute for Near East Policy think tank told the BBC that the use of children at security checkpoints "underscores the desperation of the Islamic Republic".

She said it shows "how deeply unpopular they are with their own population that it is struggling to recruit adults to staff security checkpoints and is resorting to using children in support roles during wartime".