America Movil is extending a ‘no-borders’ pricing plan from contract to prepaid subscribers in Mexico, a sign of escalating competition between operators on both sides of  the US-Mexico divide.

Last month, the operator introduced a plan that enables contract customers in Mexico to make calls to the US at local rates, while minutes, SMS and data plans can also be used when roaming across the border.

According to Reuters, a similar deal is now on offer for about 40 million of its prepaid customers in Mexico.

Users of its Amigo Optimo and Optimi Plus prepaid plans will be able to take advantage of the move, while the remaining prepaid users, numbering about 12 million, can have access to the offer on request, the company said.

Prepaid users represent the overwhelming majority of its customer base. Extending the pricing plan will therefore escalate competition with, for instance, AT&T, which has a presence on both sides of the border.

America Movil is Mexico’s biggest operator by a significant margin – it has around 70 per cent of market share, while AT&T only has 8 per cent – but is facing regulatory crackdown in the country which is trying to address the competitive landscape.

Following the new laws, AT&T bought Iusacell and Nextel and launched its “borderless” call and data plans, saying it wanted to create the first-ever North American Mobile Service area, which will cover more than 400 million consumers and businesses in Mexico and the US.

In its Q2 2015 results, America Movil’s wireless service revenue in Mexico of MXP33.58 billion ($2.12 billion) was down 8.5 per cent year-on-year.

At the time, it noted that this country is seeing “a major change in the telecommunications sector”, with AT&T ramping-up its presence in the sector and the trend for cable operators to offer triple-play packages, coupled with regulatory reforms.

It was also reported back then that the operator was set to spend $6 billion on its network in Mexico over the next three years – shortly after AT&T made a $3 billion pledge.