MONTEVIDEO, Uruguay (AP) — The legal sale of marijuana in Uruguayan pharmacies is facing challenges as banks refuse to deal with companies linked to the drug in order to follow international financial laws.

A government official said Friday that Uruguayan banks risk running afoul of laws that ban receiving money tied to the drug. The official was not authorized to comment publicly and spoke on condition of anonymity.

In July, marijuana went up for sale at 16 pharmacies as part of a 2013 law that made Uruguay first to legalize a pot market covering the entire chain from plants to purchase.

But one pharmacy in the capital, Montevideo, has decided not to sell it after a warning by a local branch of Spanish bank Santander. The bank said it has opted to remain out of this line of business.

State-owned Banco Republica, Uruguay's largest bank, also told pot-selling pharmacies that it must close their accounts.

Some U.S. marijuana retailers in states that have legalized sales have encountered similar banking difficulties as the drug remains illegal on a federal level.

Diego Olivera, secretary-general of Uruguay's National Drugs Council, said authorities are meeting with the pharmacies to find out how many have been warned by banks. He added that officials are looking at possible solutions, but did not give details.

"Without doubt, in these processes of changing paradigms, they run up against moments of difficulty," Olivera said. "We are working on alternatives."

Sen. Jose Mujica, who was president when legalization passed in 2013, has threatened "gridlock" in parliament if authorities fail to resolve the problem for what was one the signature policy initiatives of his administration.

Pharmacy lawyer Pablo Duran told Carve radio that the pharmacies selling marijuana operate within the law in "an activity that is completely regulated, licit ... and controlled."

Running a business without being able to bank is tough in Uruguay. Among other things, the law prohibits cash or check payments for employees and requires that salaries be paid by direct deposit.