Taxi-hailing services Careem and Uber suspended operations Saturday in Abu Dhabi – without any explanation.

The rival companies, which both began operating in Abu Dhabi in 2013, have acknowledged the temporary shutdown in in-app messages to users but have not explained why they suspended service or said when they expect to resume operations.

“This is a temporary suspension and we will let you know of any further updates,” an Uber spokesman in Dubai told Reuters .

Both companies are still operating in the neighboring emirate of Dubai.

The National quoted Careem as saying that they were working with Abu Dhabi's taxi regulator on the issue.

"Due to some unforeseen circumstances, we expect potential service interruptions in Abu Dhabi over the next few days," the company said. "We work with licensed vehicles in Abu Dhabi and we are working closely with TransAD to ensure both a reliable service and adherence to fleet requirements."

StepFeed has reached out to both companies for comment.