MEXICO CITY (Reuters) – America Movil, the telecommunications company of Mexican tycoon Carlos Slim, and Movistar, the Colombian unit of Spain’s Telefonica SA, may not have to pay any compensation while legal action in Colombia is under review, a government minister said on Wednesday.

Shares of America Movil closed down 0.32 percent and Telefonica shares closed up 1.38 percent after a Colombian arbitration panel on Tuesday ordered America Movil to pay $1 billion and told Movistar to pay $529 million.

David Luna, Colombia’s minister for information technology and communications, said in a radio interview that the companies can request suspension of the payment while the case makes its way through Colombia’s Council of State, the highest judicial authority for rulings involving the government.

“They have established rights and obviously it’s their choice whether or not they use them,” Luna said.

The panel said the two rivals failed to return installed telecommunication networks and infrastructure as part of agreements to provide cellular phone service more than a decade ago, the government’s legal defense agency said.

Original contracts signed in 1994 agreed that networks would be returned to the state in 10 years.

New contracts were later drawn up eliminating the return of the networks, but were overruled by another legal authority that argued that the original contract could not be modified.

Movistar could not be reached for comment. Slim’s company, Latin America’s largest telecoms firm by subscribers, said it would seek legal advice.

America Movil said it rejected the change to the legal framework in Colombia, noting that it had made major investments under the existing one.

“(These are) changes that affect elements as indispensable as the right to private property and the legal certainty necessary for encouraging investments in the country,” the company said in a statement.

A legal expert questioned whether the firms would end up having to pay those amounts.

The proposed payment is “a mere formality of a legal process that isn’t over yet,” said Ramiro Tovar Landa, a professor at the Autonomous Technological Institute of Mexico.

The dispute is sensitive for America Movil as Colombia is one of its most important markets, Intercam Casa de Bolsa wrote in a note to investors.

“The operations in Colombia have shown improvement in the latest quarters, but the regulatory risk continues to be important in the country,” Intercam wrote.