Loss-making national carrier Kenya Airways canceled several flights on Sunday after some crew members failed to turn up for work, the latest blow as the airline struggles to avert a strike called by its pilots.

"Some of our outsourced staff, including cabin crew, have stayed away from work from Friday and we are working with their employer to resolve any issues they may have," the airline said in a statement.

Flights to the Kenyan city of Mombasa, Kilimanjaro in Tanzania, Juba in South Sudan, Lusaka in Zambia, Harare in Zimbabwe and Maputo in Mozambique were canceled because there were not enough crew members to fly safely.

Kenya Airways later said that normal service had resumed but offered no further details.

Pilots unio KALPA has called an indefinite strike, scheduled to start on Tuesday, to protest against the management of the airline, which is part owned by the government and Air France KLM.

The unio said its members had lost confidence in the ability of the airline's chief executive and chairman to end years of losses. On Friday, a court ruled the strike was illegal and the government had said it would be "economic sabotage". On Thursday, the airline said it had halved its pre-tax loss to 5 billion shillings (US$49.4 million) in the past six months thanks to a recovery in passenger numbers.