The German military has been forced on the defensive after young children were photographed holding and pointing a range of automatic weapons during last Saturday's public "Day of the Bundeswehr" at 16 military bases across Germany.

The photos, taken at a military base in Stetten, in the southern state of Baden-Württemberg, were posted online by the German Peace Society (DFG-VK), along with a blog post that said that a "boundary had been crossed."

The 15 photos posted online show five different children, all under 12 years old, holding a range of standard military weapons, identified by the DFG-VK as the G36 assault rifle, the G28 sniper rifle, and the MP7 submachine gun, all made by Germany's leading (and most controversial) gun-maker Heckler & Koch.

According to the DFG-VK, this violated one of the Bundeswehr's own guidelines for its public events, published by the Defense Ministry in 2011, which states that "children and young people up to the age of 18 must not be given access to small arms or ammunition."

Denials - called out

Both the Bundeswehr and the Defense Ministry moved quickly to contain the damage this week. Stetten's garrison commander Hansjörg Friedrich denied that any breach had happened at all. "It wasn't our soldiers that gave the weapons to the children, this happened on the parents' initiative," he told the local "Schwäbische Zeitung" on Wednesday.

As soon as the commanding officers saw what was happening, he added, they warned the parents that the children should not be given the guns, but it was not always possible to prevent them, because of the "big crowd."

This, according to DFG-VK's Roland Blach, is a lie. "I know from at least four people that it happened as we showed it," he told DW. "Maybe he was talking about cases he knows about, but we know of the cases that were published, and were documented, that this is was what happened. We have several witnesses who saw it."

Defense Minister Ursula von der Leyen, who gave the welcome address for the open day at a barracks in Frankenberg, Saxony, promised that this would not happen again. "In order to rule out something like this in the future, I have decided that no more firearms will be presented for holding at Bundeswehr days," she told the RND newspaper network. She described the incident in Stetten as "a regrettable mistake that happened despite clear regulations."

Friedrich also promised a thorough investigation, and that there would be disciplinary consequences if any rules had been broken. "But at the moment I don't see any dereliction of duty," he added.

Advertising the military to children

But activists like Blach think that there is deliberate strategy involved. "Maybe there are problems in the chain of command, but for us it was clear that the soldiers were handing the weapons to the children, and showed them how to use them," he said.

Blach also claimed that at least one witness heard a soldier say, "This is really against the regulations, what I'm doing here," and that there were reports of similar incidents at another military base during the open day at Münster. "I would say there is a system behind it, to look the other way and allow the children to look at the guns," he said.

The Bundeswehr, which is in transition from being a conscript to a volunteer army, is under pressure to find new recruits.

The "Day of the Bundeswehr" was only inaugurated last year, and involves the participation of 10,000 soldiers and attracted over 260,000 visitors. But there have been other incidents at public demonstrations in the past - in 2011, a base in Bad Reichenhall, Bavaria, was criticized for allowing children to try out targeting systems for rocket launchers.

The German military has also previously been warned by the United Nations about advertising to children. In a 2014 report on Germany, the UN's Convention on the Rights of the Child (CRC) noted that, "Some advertising campaigns for the armed forces specifically target children, and representatives of the armed forces are sometimes present within the school context, speaking with pupils and organizing activities," and urged Germany to legislate against it. So far, this hasn't happened.