Lebanese flag carrier Middle East Airlines (MEA) on Thursday warned striking pilots that they faced dismissal unless they go back to work.
"The company is going to begin implementing legal measures to dismiss pilots who don't show up to work," MEA chairman Mohammed Hout told AFP.
The pilots were due to end a 48-hour strike over the dismissal of a cancer-stricken colleague on Wednesday evening but decided to prolong their action after the company withdrew five days worth of wages.
MEA also sent a warning letter to each striking pilot threatening dismissal.
Captain Fadi Khalil, head of the pilots' union, said the strike would continue until the company paid the full salaries and withdrew the warning letters.
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"We will go on with the strike until the company pays us our full salaries and withdraws the warnings," Khalil said.
"We denounce the company's actions," he added. "It's as though they are pushing us to go on with the strike."
Hout said the airline was incurring heavy losses because of the strike which has heavily disrupted traffic and grounded most flights.
The MEA pilots initially announced a strike from 2000 GMT on Monday to 2000 GMT Wednesday, covering all flights, over the sacking of the cancer-stricken captain.
Khalil said the captain had served the airline for 38 years and was laid off as soon as he went on sick leave.