Telekom Austria's shareholders on Thursday gave the go-ahead for a rights issue of up to 1 billion euros ($1.3 billion) and approved the company's new supervisory board, which is controlled by representatives of the company's new majority owner, Mexico's America Movil.

The rights issue was approved by 98.1 percent of shareholders at an extraordinary general meeting.

In April, Mexican multi-billionaire Carlos Slim's America Movil and Austrian government holding company ÖIAG reached an agreement to combine their stakes in Telekom Austria and jointly control the telecommunications firm.

Through a subsequent buyout offer, America Movil acquired an additional 23.47 percent of TA's shares to raise its stake from 27 percent to just over 50 percent.

The Austrian government maintains a 28 percent stake in Telekom Austria, giving it veto power over strategic decisions.

Telekom Austria on Wednesday reported a first-half net loss of 317.8 million euros ($425 million), attributed to poor results in various Eastern European units.

The company is counting on the takeover by America Movil to shore up its finances and ensure its financial health in the future, while Slim's group wants to use Telekom Austria as a springboard for an expanded presence in Europe.

TA, which has roughly 23 million fixed-line and wireless subscribers in eight countries of central, eastern and southeastern Europe, posted nearly 4.2 billion euros (around $5.7 billion) in revenue in 2013 and had 16,000 employees at the end of last year.

America Movil, the telecommunications services leader in Latin America, had 279 million wireless subscribers and 69 million fixed revenue generating units in the Americas at the close of last year.