Ex-glam rock star Gary Glitter has been accused of having sex with two girls, one aged 12, police in Vietnam said.
An arrest warrant was issued for Gary Glitter last week
Police said the girls, 12 and 18, said in police interviews they had sex with Glitter, 61, at his Vung Tau home.
There are conflicting reports as to whether the second girl had turned 18 - the legal age of consent in Vietnam.
Glitter, whose real name is Paul Francis Gadd, has not been charged and remains in custody. If convicted he could be jailed for up to 12 years.
A Foreign Office spokeswoman said: "We are aware of the arrest of a British national and consular support is being provided."
Under Vietnamese law, sexual contact with a minor carries varying degrees of penalty, depending on the charge.
The 1970s rocker was held on suspicion of "lewd acts" with children after an arrest warrant was issued last week.
He was stopped at Ho Chi Minh City airport on Saturday by an official who recognised him from media coverage.
"Obscene acts with a child" can lead to 12 years imprisonment while child rape carries the maximum penalty of death before a firing squad.
A police officer in Vung Tua said: "Having sex with a 12-year-old girl, regardless of whether he had her consent, is still considered child rape under Vietnamese law."
Police would not confirm whether either of the girls claimed they were paid for sex.
British consular officials visited Glitter in Vung Tau, the coastal town where he has lived for six months, following his arrest.
A Vietnamese foreign ministry spokesman said after Glitter's arrest that authorities had interviewed a 15-year-old girl they had found at his home.
British officials earlier confirmed that Glitter would have access to a lawyer.
They described the Vietnamese authorities as very co-operative.
Vung Tua police said on Monday they were continuing to investigate the case and are to question the singer further.
Glitter was found guilty in the UK in 1999 of possessing child pornography and served two months in jail.