(Adds Indian government no comment, tax case background,details)
NEW DELHI, May 7 (Reuters) - Vodafone Group Plc hasbegun an international arbitration against the Indian governmentin a more than $2 billion tax case, toughening its stance in along-running dispute that has dented foreign investor sentiment.
The British mobile phone operator was widely expected to gofor an international arbitration after its talks with the Indiangovernment failed to find a solution last year.
Vodafone, which last month took full ownership of its Indiaunit after buying the 15.5 percent it did not already own, filedfor the arbitration on April 17, it said in a statement onWednesday. It did not give details.
A spokesman for the Indian finance ministry, which was intalks with Vodafone over the dispute, declined immediatecomment.
The tax dispute stems from Vodafone's acquisition of Indianmobile assets from Hutchison Whampoa in 2007.
In 2012, India's Supreme Court ruled that Vodafone was notliable for payment of any tax on the acquisition. The Indiangovernment later that year changed the rules to enable it to taxdeals that had already been concluded.
Uncertainties over policy in India have unsettled investors,and tax claims on foreign companies have been a major concern.IBM Corp, Royal Dutch Shell Plc and Nokia Oyj are among foreign firms contesting local tax claims. (Reporting by Devidutta Tripathy and Sumeet Chatterjee; editingby Jane Baird)