The move came ahead of the vote to pick the ECB's top banking supervisor and were returned after the appointment of Deutsche Bundesbank Vice-President Claudia Buch to the position, the sources said.
The decision to seize the phones was made a day after the news agency reported that the bank would raise its key inflation forecast. The report had an impact on the forecasts of many economists, who were expecting no interest rate hike from the ECB, the report said.
On Thursday, the ECB unexpectedly raised its benchmark interest rate by 25 basis points to 4.5% per annum, a new all-time high, the regulator announced.