BRASILIA (Reuters) - A move by Brazil's telecommunications industry watchdog to analyze whether to remove Oi SA's OIBR4.SA operating license will further complicate Latin America's largest-ever bankruptcy protection case, now in its 15th month, a person with knowledge of the matter said.

The headquarters of the Brazil's largest fixed-line telecoms group Oi, is pictured in Rio de Janeiro, Brazil, June 22, 2016. REUTERS/Sergio Moraes

The person, who asked for anonymity to discuss the issue freely, said Thursday’s announcement by regulator Anatel was “surprising,” given that a vote on Oi’s in-court reorganization plan was scheduled for Oct. 9. Talks between shareholders and creditors are “going well,” the person added.

Earlier in the day, Anatel President Juarez Quadros said the request by fellow councilor Igor de Freitas to cancel Oi’s operating license must be dealt with promptly, unlike similar cases in the past. Anatel has repeatedly voiced concern about the slow pace at which Oi’s creditor protection case is moving.

“What investor or creditor is going to engage in a plan to save the company with a knife on their necks?” said the person.

Oi’s in-court reorganization, which started in June 2016, has been marked by a series of disputes between creditors and shareholders. Such rifts have led the government to threaten to intervene should stakeholders fail to reach an agreement.

Preferred shares in Oi dropped 3.8 percent to 3.56 reais. The stock is up 59 percent this year.

Rio de Janeiro-based Oi said late on Thursday that it was “not aware of the arguments that could create a basis” for the cancellation of its operating licenses. It claimed that it had met all legal procedures in the bankruptcy case.

A government official who asked not to identified told Reuters that Anatel’s decision to analyze a potential license cancellation stemmed from a court decision this week to include a 13 billion-real ($4.1 billion) fine that Oi owes to the watchdog in the restructuring plan.

Another official said Anatel was seeking to press Oi shareholders to agree on a capital injection and a subsequent dilution of their stakes, should creditors decide to swap part of their debt for shares of the carrier.

($1 = 3.1404 reais)