Air Canada flight attendants ended a three-day walkout that had forced hundreds of flight cancellations after reaching a tentative agreement with the airline.

The deal was reached early Tuesday after a mediated negotiation session that lasted more than nine hours, the union’s bargaining committee said in a post on its website.

“The Strike has ended,” the union said, addressing members. “We have a tentative agreement we will bring forward to you.”

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Air Canada said separately that it planned to gradually resume service, with the first flights starting Tuesday evening. “Customers may book and fly with confidence,” the airline said.

Flight attendants walked off the job on Saturday in a dispute over pay and conditions such as compensation. The move disrupted travel at airports across Canada and forced the country’s biggest airline to withdraw its financial outlook for this year.

The union raised the stakes by defying an order by Canada’s labor board to return to work, but talks resumed Monday evening as both sides sought to break the deadlock.

READ MORE: Air Canada cabin staff go on strike, grounding hundreds of flights

The union — the Air Canada Component of CUPE — didn’t offer details of the tentative deal, which it said was reached at 4:23 am local time.

“We are required to advise our membership that we must fully cooperate with resumption of operations,” the union said.