US telecommunications giant AT&T and Egyptian billionaire Naguib Sawiris are looking to acquire a controlling stake in Italy's largest phone company, Telecom Italia, from its financial backers.

AT&T and Sawiris have both reached out to the investors planning to sell their shares in the troubled phone company, reported Reuters.

Telecom Italia is 22.4% owned by Telco, which is controlled by Italy's biggest insurer Assicurazioni Generali, Europe's biggest telecoms operator by revenue Telefonica and Italian banks Intesa Sanpaolo and Mediobanca.

Generali and Mediobanca have said they propose to sell their shares in Telecom Italia and shareholders can exit the Telco pact this month, or in August 2014, reported Bloomberg.

AT&T and Sawiris had not tabled a formal expression of interest, said the Reuters report, citing an anonymous source.

Earlier, the same source told the news agency that Mexican billionaire Carlos Slim's America Movil had also contacted Telecom Italia's controlling shareholders.

Pursued by Reuters, AT&T refused to comment while Sawiris could not be reached for a comment.

Movil's Chief Financial Officer Carlos Garcia Moreno "categorically" denied his company had approached the Italian firm's shareholders.

The board of Telecom Italia is scheduled to meet on 19 September, when the company is expected to discuss the potential change in ownership.

Telecom Italia's stock was trading 1.81% lower to €0.596 at 4:20pm in Milan on Friday, valuing the company at €11.48bn. The stock closed 8.39% higher at €0.607 the previous day.

"Whatever is decided, if there is anything to be decided, will be discussed at the appropriate time and namely at the board meeting of 19 September of Telecom Italia and the following ones. So there will be lots of time to discuss," Telecom Italia Chairman Franco Bernabe said, on the sidelines of a telecoms conference in Brussels.

The Telecom Italia board has so far rejected two investment offers. Earlier in the year, it rejected an offer of a possible merger with Hong Kong-based Hutchison Whampoa's Italian mobile unit. Last December, it turned down a €3bn (£2.5bn, $3.9bn) investment proposal from Sawiris.

"The acceleration in the sector's consolidation and Telecom Italia's and its holding company's difficulties support the idea of extraordinary operations," ICBPI brokerage said in a note, and added that the likely exit of Mediobanca and Generali from the Telco accord by 28 September was fueling speculation on the stock.

Debt-laden Telcom Italia is viewed as a potentially attractive acquisition target post the recent Vodafone-Verizon deal.

Earlier in the week, Verizon Communications confirmed a $130bn deal with Vodafone to acquire its 45% stake in the pair's profitable US joint venture, Verizon Wireless.

Vodafone, the world's second-largest mobile operator, is also viewed as a potentially attractive acquisition target by AT&T, which could be interested in Vodafone's assets, primarily those in Europe, at the conclusion of the British firm's Verizon Wireless deal.

An acquisition in Europe will help AT&T cash in on the growing demand for faster Internet services across the region. Vodafone rolled out its 4G network in London last month, at a time when several countries in Europe await the roll out of faster connections.