Fresh labor unrest is brewing at cash-strapped national carrier Air India as more than 100 pilots threatened to resign over alleged discrimination by the company.

About 10 international flights were canceled on Oct. 31 as 23 Air India pilots reported sick, an airline official said.

The threat of mass resignations comes after management initiated a training program in the U.S. for pilots to fly the Boeing 787, the first of which is expected to join the airline by next month. Meanwhile, government authorities and the pilots’ union are trying to resolve the issue. Civil Aviation Minister Vayalar Ravi says talks are beginning between management and pilots, and he hopes the matter will be resolved soon.

In letter to management, 100 pilots represented by the Indian Pilots’ Guild (IPG)—some of whom were members of the pre-merger Air India—said they were considering seeking employment elsewhere. Air India, however, said its pilots have not called for a strike, and it rejected reports of threatened resignations.

“A section of the press has reported that Air India pilots have given a call for strike while some pilots have reported sick, and that flights have been canceled due to ... pilot agitation. It is also rumored that a number of pilots have written to the Air India management asking ... to leave their jobs. Air India would like to clarify that there is no strike call given by any section of employees of Air India and there is no agitation by the pilots,” the carrier’s statement read.

The airline also said flight delays on Oct. 31 were due to a shortage of cabin crew.

An airline official said the trouble started when 64 pilots—32 from IPG and 32 from the Indian Commercial Pilots Association, the union of former Indian Airlines pilots—were selected to undergo 787 training in the U.S.

The pilots claimed in the letter to management that their peers at Indian Airlines received favored treatment, “leading to a complete stall of our career progression.”

“We, the loyal employees of Air India working for past several years feel cheated by management’s unfair and discriminatory decisions,” said a letter sent Oct. 29 to Air India’s chairman and managing director, Rohit Nandan.

“We are deeply pained by this discriminatory attitude that the management has adopted toward us vis-a vis-the pilots of erstwhile Indian Airlines. Therefore, we are compelled to seek a no-objection certificate, so that we may consider seeking employment elsewhere,” the letter said.

An Air India spokesman said, “Talks are on to sort out the issue. We hope to resolve the problem.”

The airline suffered a 10-day strike that started in April and caused a revenue loss of 1.5 billion rupees ($30 million) when 1,600 flights were canceled. The airline is incurring monthly losses of more than 6 billion rupees. It has a cumulative debt of 400 billion rupees from aircraft acquisitions and short-term loans to maintain its operations.