Russian operator group MTS said US financial authorities have asked it to cooperate in their investigation of the telecoms market in Uzbekistan, according to Reuters.

The group said the Securities and Exchange Commission (SEC) requested documents and information related to its business in Uzbekistan, which it was forced to abandon in 2012.

The SEC investigation concerns “the activities of unaffiliated parties” according to MTS.

MTS did not state whether it has provided the documents or plans to do so, but Alexei Kornya, the company’s CFO, said the offer to provide documents is voluntary and concerns the activities of third parties.

The operating licence held by MTS in Uzbekistan was revoked in 2012 by the country’s government which also confiscated the company’s assets, forcing it to write down around $1 billion.

Operator groups TeliaSonera and VimpelCom have also been asked to provide information by the SEC regarding their dealings in the central Asian country in recent days.

Sweden-based TeliaSonera was also told it is subject to an ongoing investigation related to its transactions in Uzbekistan by the US Department of Justice.

In addition, Dutch authorities targeted TeliaSonera UTA Holding and TeliaSonera Uzbek Holding, both based in the Netherlands, as part of a “preliminary investigation concerning bribery and money laundering”.

The Nordic group was previously embroiled in controversy related to its operations in Uzbekistan, with a probe into whether it was aware that the money it spent to acquire an operating licence in the country in 2007 went to the family of Uzbek president Islam Karimov.

TeliaSonera’s CEO Lars Nyberg resigned early last year after a Swedish law firm hired to investigate the issue criticised the company for not making sufficient effort to investigate the local partner or how it “could hold the rights that were later transferred”.

VimpelCom said last week that it is being investigated by US and Dutch authorities in connection to its operations in Uzbekistan and that it fully intends to cooperate on the matter.

Its head office in Amsterdam was visited by Dutch officials who obtained documents and informed the company that it is “the focus of a criminal investigation” in the Netherlands.

According to Reuters, VimpelCom warned of the potential for an investigation in 2012 due to its relationship with Gibraltar-based company Takilant, which was part of an inquiry by Swedish authorities into TeliaSonera’s 2007 purchase of a 3G licence in Uzbekistan.