Verizon Communications Inc. has agreed to purchase 43.4 million shares of MCI Inc. common stock for $25.72 per share from eight entities affiliated with billionaire Carlos Slim Helu in the fight between Verizon and Qwest Communications International Inc. to acquire MCI.

While this was an opportunity for us to purchase a block of shares under unique circumstances and is an important step forward in our acquisition of MCI, we will continue to assess the situation as we move toward a vote by the MCI shareholders, Verizon Chairman and CEO Ivan Seidenberg said in a statement on Saturday.

Some MCI shareholders are angered that Verizon is paying the Slim entities more for a 13 percent stake in MCI than what it is offering other MCI shareholders in the $7.64 billion agreement to acquire the Ashburn, Va., long-distance phone carrier, according to national media reports. Verizon has agreed to pay MCI shareholders $23.10 a share.

By entering into its deal with Mr. Slim, Verizon has both created two classes of shareholders and called into question the MCI boards previous determination that Verizons lower offer to the other MCI shareholders was superior and fair, Qwest said in a statement.

Last week, Qwest said MCI shareholders asserting to own more than half of MCIs outstanding shares indicated in a survey they believe the Qwest offer for MCI is currently superior and they would support it.