The German Chancellor has said that reports of US spying are straining transatlantic relations and putting a US-EU trade deal to the test.

Angela Merkel, whose mobile phone was allegedly bugged, told a special parliamentary debate on surveillance by the US National Security Agency that all light must be shed on the matter.

“The allegations are serious. They must be investigated and more importantly, new trust has to be re-established for the future,” she told the lower house, the Bundestag.

Spying allegations are especially sensitive in Germany after the Nazi and communist eras. Merkel grew up in the former East, where spying by the Stasi on ordinary citizens was rife.

Merkel says ties with the US are of “paramount” importance , but one opinion poll suggested six out of ten Germans did not think the US was a partner to be trusted.

Berlin still wants to talk to Edward Snowden, though the whistleblower who is in Russia will not be invited to Germany.

The country fears being put und