Verizon Communications

(VZ) - Get Report

on Saturday said it agreed to buy 43.4 million shares of



held by its largest shareholder, Carlos Slim Helu, for $25.72 each in cash, or $1.12 billion, setting back recent takeover efforts by

Qwest Communications



The purchase of the 13.7% stake, which is subject to regulatory approvals, is expected to close in several weeks.

Verizon's acquisition, which would make the company MCI's largest shareholder, is the latest salvo in the two-month tussle for control of MCI. Earlier in the week,

MCI accepted Verizon's $7.6 billion takeover offer over a $9.1 billion bid by Qwest.

In a statement, Verizon CEO Ivan Seidenberg said, "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."

Additionally, under the agreement, Verizon said it would pay Slim's entities a bonus after one year, in an amount per MCI share equal to 0.7241 times the amount by which the price of Verizon's common shares exceeds $35.52, measured over a 20-day period.

On Friday, shares of MCI closed the regular session up 21 cents to $25.84; Qwest shares rose 13 cents to $3.93; and Verizon shares fell 34 cents to $35.07.