Swiss authorities are investigating Gulnara Karimova, daughter of Uzbekistan's President Islam Karimov, on suspicion of money laundering.

Switzerland's prosecutor said in a media statement that it has widened its money laundering probe after initially centring its investigation on four people with business and personal ties to Karimova.

The Swiss authorities added that it had since blocked more than nearly one billion dollars in funds linked to alleged irregularities in Uzbekistan's telecommunications market.

Karimova, who is a fashion designer and a popstar, known under the stage name of Googosha, has always denied allegations of business impropriety against her, but her whereabouts are currently unknown.

Earlier today, Russian mobile phone operator Vimpelcom announced that the US Securities and Exchange Commission and Dutch authorities are investigating the group in connection with its operations in Uzbekistan.