BRUSSELS - The European Union (EU) said it has questioned US authorities about alleged spying on EU offices, media reports said on Sunday.

The EU has contacted with US authorities immediately and demands "full clarification" after a report made by German weekly Der Spiegel claimed that Washington bugged EU offices in Brussels and the US, an EU statement was quoted as saying.

Washington has not responded to the questioning yet, according to the reports, adding that the Der Spiegel said on Sunday its report was based on confidential documents, some of which it had been managed to consult via fugitive ex-CIA analyst Edward Snowden.