MOSCOW, April 10 - RAPSI. The High Court of Justice of the Isle of Man has increased the pledge in MTS subsidiaries' lawsuit against Altimo, which manages Russian Alfa Group's telecom assets, to $900 million worth of shares, reports citing Altimo.

In November 2011, the court set the pledge in the same lawsuit at $500 million worth of Vimpelcom shares held by Altimo.

The lawsuit was filed by MTS subsidiaries Kyrgyz Mobil Tel, Flaxendale and George Resources (KFG) to regain MTS's ownership of 51% of the Kyrgyz operator Bitel, which MTS bought for $150 million in 2005. However, the Supreme Court of Kyrgyzstan transferred the stake to little-known Russian company, Rezervspetsmet. The shareholding was later turned over to Sky Mobile and following several more transactions, one of which involved Alfa Group, to Russia's VimpelCom.

VimpelCom is 100% owned by the Vimpelcom Ltd holding company, in which Altimo holds 47.85% of voting shares and is therefore one of the mobile operator's largest beneficiaries. The other major beneficiary of Vimpelcom Ltd. is Norway's Telenor, with 42.95% of the holding's voting shares.

MTS and VimpelCom are two of Russia's top three mobile operators.