Italy’s antitrust authority said on Wednesday it had opened an investigation into whether Apple Inc (AAPL.O) and Amazon Inc had engaged in anti-competitive cooperation in the sale of Apple products and Beats headphones.

It said the investigation was aimed at establishing whether Apple and Amazon had reached an anti-competitive agreement to prevent electronics reailers not included in Apple’s official programme to sell the products.

It added that Antitrust officials searched Amazon and Apple offices in Italy on Tuesday.

(This story corrects date of searches to reflect corrected statement from the antitrust authority)