(QHA) - An EU summit is due to begin in Brussels with fresh allegations of US spying threatening to overshadow talks. It comes a day after German Chancellor Angela Merkel called President Barack Obama over claims that the US had monitored her mobile phone, BBC informs. Mrs Merkel says she wants US officials to clarify the extent of their surveillance in Germany. "Among close friends and partners, as the Federal Republic of Germany and the US have been for decades, there should be no such monitoring of the communications of a head of government," reads the statement of Merkel’s spokesman. Suddeutscher Zeitung - one of the country's most respected papers says an attack on Angela Merkel's mobile phone would be an attack on "her political heart". As reported earlier the US is being called to account by its allies over allegations of spying based on material said to originate from fugitive American leaker Edward Snowden.