European Union merger watchdogs said they stopped the clock on their review of Boeing’s tie-up with Brazilian rival Embraer for a second time as they demanded yet more details from the jet makers.

The move is a rerun of a similar request late last year for data about the deal, which the European Commission has warned could remove Embraer as the third-largest global competitor to both Boeing and Airbus, leading to higher prices and less choice.

“This procedure in merger investigations is activated if the parties fail to provide, in a timely fashion, important information that the commission has requested from them,” the commission said in an email.

Once the missing information is supplied by the parties, “the clock is restarted and the deadline for the commission’s decision is then adjusted accordingly,” the EU authority added.

While such requests can be a signal of difficulties with a deal review, they are relatively common when regulators are probing complex transactions. Typical information sought by the EU would include details of how the two companies compete with each other in aircraft markets.

The delay will push the EU’s deadline for a decision beyond a previous April 30 date, frustrating the companies’ efforts to close the deal early in 2020. Brazil should approve the deal this month, a person familiar with the discussions said last month. It has been cleared without conditions in the U.S. and China.

Boeing plans to take an 80% stake in a venture controlling Embraer’s commercial airplane and services businesses, in order to better compete with Airbus after its rival took control of Bombardier’s C series aircraft in 2018. Boeing and Embraer had to move their target for completing the deal to early 2020.

“We continue to cooperate” with Brazil and the EU commission “as they progress their assessments and look forward to a positive outcome,” Boeing said in an emailed statement.