France's national football team was further drawn into the sex scandal involving Franck Ribéry yesterday after two more players' names were cited in connection with an investigation into underage prostitution.

Unnamed judicial sources told the French media that Karim Benzema, the Real Madrid forward, and Hatem Ben Arfa, a striker for Marseille, are expected to be questioned in coming days as "witnesses" in the inquiry.

The scandal engulfing Les Bleus, which began when Ribéry was questioned by police in connection with a prostitution ring, also deepened after judicial sources said the 27-year-old had admitted having sex with a 17-year-old prostitute but denied having known she was underage. In France it is illegal to buy sex from someone under 18.

The Bayern Munich forward's lawyer, Sophie Bottai, has insisted that, while the footballer did provide witness testimony to French investigators looking into a ring allegedly run out of a Paris nightclub, he was being heard simply as a witness and not as a suspect.

No charges were filed against him, said Bottai, and he was not held in police custody.

However, the rumours swirling around the team have not ceased since reports surfaced at the weekend that Ribéry and his fellow player Sidney Govou had been questioned by French investigators.

On 12 April police had searched the Zaman Café, a restaurant and nightclub on the Champs Elyseés, and arrested a dozen people, among them prostitutes and a man suspected of being their pimp.

Refusing to say whether or not his client had been questioned by police, Govou's lawyer, Thierry Braillard, said the 30-year-old had "never set foot" in the Zaman.

But the player's name has been cited repeatedly in connection with the investigation being led by the investigating judge André Dando. A judicial source said that, while his married team-mate Ribéry remained a witness in the affair, "it is up to the judge to decided whether to formally investigate him [Ribéry] or not".

In France, prostitution is legal but several activities surrounding it are against the law. If found guilty of paying an underage sex worker, a client could go to prison for three years and be fined up to €45,000 (£39,000).

Yesterday the two other players drawn into the scandal vehemently denied involvement in alleged activities at the Zaman, which has now been shut down. "It's absolutely not me," Ben Arfa told L'Equipe TV. Even if his client were summoned by the police tomorrow, added his lawyer, "that would change nothing".

Benzema's agent, Karim Djaziri, also spoke out in defence of his client. "Karim has not been questioned. He has nothing to do with this affair," he told LePost.fr.

As speculation mounted in Paris, the French football federation (FFF) issued a terse statement saying it was aware of the investigation and certain players' involvement "as mere witnesses". But it said it would "refrain from all comment" until the police had done their job.