Mobile phone group Vodafone could sell its stake in its joint venture with Verizon Communications for about $48 billion (25 billion pounds) before the end of the month, according to the Observer newspaper.

The deal for Vodafone's 45 percent stake in U.S.-based Verizon Wireless would total $56 billion, including debt, the newspaper said.

Sources have told Reuters that Verizon has held talks with Vodafone over the sale.

On Tuesday, the Daily Telegraph newspaper said in an unsourced report that Verizon valued the stake at $38 billion, $12 billion below Vodafone's valuation.

Vodafone was not immediately available, but has repeatedly said it has no plans to sell.