Two migrants claiming to be 15 and 17 have been arrested after an alleged sex attack on a 12-year-old girl at a home for underaged refugees in Germany.

The pair allegedly targeted the victim independently at the housing for unaccompanied minors in Dusseldorf, with at least one of the attacks being witnessed by another child.

However, the six-year-old witness had not reported the incident to staff after one of the attackers threatened to 'cut his throat' if he told on them, according to local media.

The two asylum seekers both claim to be under 18 and had been place in the same housing as the 12-year-old girl they allegedly assaulted (pictured are migrants and refugees waiting outside a registry office in Berlin)

Days after Swedish police admitted they had no ID for a Somalian '15-year-old' who allegedly murdered a social worker, German police also say they have no proof of age for the perpetrators.

They are now being kept in custody while police frantically try to investigate the alleged sex attack and confirm their claimed ages.

Dusseldorf prosecutor Ralf Herrenbruck confirmed: 'The court has confirmed that they need to be kept in custody and are charged with sexual abuse of a child and making threats.'

The allegations against the pair suggest that they had both separately taken the opportunity to take advantage of the 12-year-old on 24th of January this year .

The pair, who also threatened to kill a six-year-old boy who witnessed the alleged sexual assault, had told German border police they were 15 and 17, but their age has not yet been proven

Both the alleged attackers and their victim was staying at the government-provided housing where they were being given care and accommodation.

It is said they used violence to force her into sex acts, with local media reporting that the two had apparently acted independently to target the same girl.