A Kenyan magistrate has ruled that the country's athletics manager can be held by police for four weeks as they investigate claims that he was prepared to warn coaches about drugs tests in return for £10,000 ($13,000).

Michael Rotich denies any wrongdoing, saying he wanted to protect athletes.

The allegations result from an undercover investigation by the Sunday Times and German broadcaster ARD.

Mr Rotich has already been sent home from the Olympic Games in Rio.

During the operation, Mr Rotich was approached by a supposed doping specialist hired to supply banned substances to a fictional British sports team, the Sunday Times reports.

In the film Mr Rotich appears to request a one-off payment to give athletes 12 hours' advanced notice of a pending drugs test because he knew the official anti-doping testers.

Athletes are not supposed to be warned in advance of doping tests as that might help drug cheats to avoid detection.

But Mr Rotich told the newspaper he was only going along with it because he wanted to find out who the undercover reporters were and "protect" athletes.

Mr Rotich's lawyer, Ham Lagat, said after the court order that the evidence against his client "is not strong enough", AP news agency reports.

"It is tenuous, it is whimsical evidence," Lagat said. "It is about a video, it is about a newspaper, it could be a gutter press," AP adds.

Kenya was only removed from the World Anti-Doping Agency's (Wada) list of "non-compliant" countries on Friday, the day the Rio Games opened.

The country had twice failed to meet Wada's requests for anti-doping mechanisms to be put in place, with athletes facing special testing before the Games.

More than 40 of Kenya's track and field athletes have failed doping tests and been banned since