Kenya Airways said on Thursday it had cancelled all but two evening flights due to a walkout by some of its pilots, despite an agreement reached a day earlier to defer the strike until June.
Pilots oppose Chief Executive Mbuvi Ngunze's planned measures to turn around the loss-making carrier, which is 26.7 percent owned by Air France KLM, and have demanded his immediate resignation.
Instead of turning up for work on Thursday, scores of pilots attended a meeting of the Kenya Airline Pilots Association (KALPA).
The airline said the strike had effectively started, even though it obtained a court order the previous day barring any industrial action on Thursday and the pilots' union had agreed to delay the strike until June 1.
The airline said in a statement on Thursday evening that it had cancelled all but two flights until 2300 GMT, adding to the 10 cancelled earlier in the day.
"We are still consulting and negotiating with our pilot fraternity that is a vital part of our business and we hope to have an amicable agreement soon," the airline said.
KALPA issued a two-day notice to the carrier on Tuesday saying its members would stop flying planes until Ngunze resigned over what it called "questionable" turnaround measures.
The airline has been selling assets, including planes, and plans to lay off 600 people as it tries to stay in operation after three and a half years of financial losses.
Transport Minister James Macharia and Dennis Awori, chairman of the airline's board met with KALPA on Thursday but their pleas not to ground the airline's fleet were rejected.
Pilots later voted to go ahead with the strike but it was unclear when a full strike would officially begin.
"The strike is on," an airline official who declined to be identified told Reuters after members of the pilots' association voted.
Kenya Airways is one of the largest carriers in Africa, ferrying 10,000 passengers a day with a fleet of Boeing and Embraer jets.