ATSI's Mexico ATM Fiber Route to be Operational Within the Week; Technical Officer Joins Management Team; Earnings/Conference Call Details Below.

SAN ANTONIO--(BUSINESS WIRE)--June 4, 1999--

American TeleSource International Inc. ("ATSI") (OTC BB:AMTI) today announced that it has secured a fiber network between Dallas, Texas, and Mexico City through its signed agreement with Bestel S.A. de C.V. (Bestel).

Bestel is a licensed carrier in Mexico operating a 2,270-kilometer fiber optic, digital switched network. This connection completes the first phase of ATSI's Asynchronous Transfer Mode (ATM) "next generation" network between the U.S. and Mexico. ATM is an industry-standard protocol allowing high-speed transfer of voice, video and data (Internet protocol or IP) in uniform packets for switching and routing.

Under the arrangement with Bestel, ATSI will have the capability to roll the first phase of the agreement into a longer-term "dark" fiber contract. The dark fiber arrangement will secure future capacity requirements under ATSI's expansion plans within Mexico. By securing proprietary fiber, ATSI can achieve diversity and redundancy in its network, while eliminating dependency on third-party vendors and suppliers. ATM technology will increase the speed and efficiency of the network, providing ATSI customers with the highest level of quality, versatility and flexibility in the transport of their traffic.

Randy Poole, ATSI's President, stated, "We are pleased to report that as of today, our fiber route to Mexico is in the final stages of testing, which should allow for network transport within the week. Although we are disappointed by the lengthy delay in turning up this fiber route and the resulting impact to our current-term revenues, adding the fiber optic component to our existing satellite network will accomplish several vital operational goals: 1) bandwidth capacity for attracting higher profile customers, 2) diversity and redundancy for least-cost traffic routing and improved disaster recovery and 3) non-dependency on third party network vendors and suppliers. The delay is attributed to a large, well established, international vendor not delivering under the terms of their agreement with us. ATSI has taken this breach seriously, and we are pursuing available remedies."

Mr. Poole added, "As we continue deploying world-class technology and network infrastructure, we are taking steps to further enhance our planning and design capabilities. Chuck Bagby has joined ATSI's management team as Senior Vice President of Operations and Engineering, following an eleven-year career with AT&T. During Chuck's tenure at AT&T, he held several management positions within various high technology and international environments. He is fluent in Spanish, and his background encompasses telecommunications, international negotiations, international expansion, program and project management and business process re-engineering."

Arthur L. Smith, ATSI's Chairman and CEO, commented, "ATSI is laying the groundwork today for a multi-service infrastructure to economically and efficiently provide existing and new service offerings into the future. Securing fiber with Bestel adds capacity for growth and sets the stage for our evolution into a fully integrated, facilities-based telecommunications company. Furthermore, we are fortunate to have someone of the technical caliber like Chuck Bagby join senior management. He brings significant Latin American telecom experience and the network planning and design expertise necessary for ATSI's future expansion."

American TeleSource International Inc. is an emerging multinational carrier serving certain niche markets in and between Latin America and the United States. The Company's borderless strategy includes the deployment of a "next generation" network for more efficient and cost-effective service offerings of domestic and international voice and data transport. ATSI has clear advantages over the competition through its corporate framework consisting of unique licenses, interconnection and service agreements, network footprint and extensive distribution channels. ATSI's wholly owned subsidiary, GlobalSCAPE Inc. ( www.globalscape.com ) is rapidly becoming a leader in electronic commerce of top Internet-based software, utilizing the Web as an integral component of its development, marketing, distribution and customer relationship strategies.

The statements contained herein that "...our fiber route to Mexico is in the final stages of testing, which should allow for network transport within the week", "ATSI is laying the groundwork today for a multi-service infrastructure to economically and efficiently provide existing and new service offerings into the future" and "securing fiber with Bestel adds capacity for growth and sets the stage for our evolution into a fully integrated, facilities-based telecommunications company" are each considered a "forward-looking statement" as defined in the Private Securities Litigation Reform Act of 1995. These statements are based upon the belief of the Company's management, as well as assumptions made beyond information currently available to the Company's management. Because such "forward-looking statements" are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Factors that could cause results to differ materially from those expressed or implied by such forward-looking statements include, but are not limited to, price competition, the inability to obtain additional capital, loss of key personnel, unavailability of leased transmission facilities, damage, loss or malfunction of satellites, fiber cuts, technological changes, service interruptions, equipment failures, customer attrition, general economic conditions, relationships with vendors, government supervision and regulation, changes in industry practices and other factors discussed in filings made by the Company with the Securities and Exchange Commission.

ATSI EARNINGS CONFERENCE CALL

The conference call will be held on Tuesday, June 8, 1999, at 10:00 a.m. CST.

To participate in the conference call dial 888/222-2994.

For your convenience, the call will be recorded and may be replayed by dialing 973/694-6836. This service will be available beginning at 11:00 a.m. Tuesday, June 8, through 7:00 p.m. and Wednesday, June 9, beginning at 7:00 a.m. through 7:00 p.m. CST.