US senators reportedly urged India to relax its stance on citizens’ data being stored locally, days before a controversial new law on information related to payments came into force.

According to Reuters, two senior politicians wrote directly to India’s prime minister warning the country’s position on retaining consumer data within its borders could ultimately represent a “key trade barrier” with the US.

The two senators – John Cornyn and Mark Warner – co-chair of the senate’s cross-party group dedicated to issues related to the US’s relationship with India.

Dated Friday, the letter came three days before the India’s central bank imposed regulations on payment providers requiring all information on financial transactions within the country to be stored domestically.

The law comes into force today (15 October) and sparked controversy when announced earlier this year as US payment providers – including MasterCard and Visa – claimed it hampered international fraud detection measures, among other issues.

Costs associated with storing the required data locally for providers based outside of India is thought to run into the millions.

Other grievances related to the new regulation include the perceived short-time scale to meet new standards, as The Reserve Bank of India gave companies just six months to comply.

Although US payment giants called for a revision of the rules, in July India-based rival Paytm – which already has its central infrastructure in the country – backed the measures and strongly opposed any watering down of the law.