A German delegation of intelligence officials is in Washington for talks at the White House today following claims that the US monitored Chancellor Angela Merkels mobile phone.
The chancellors foreign policy adviser and Germanys intelligence co-ordinator will hold talks at the White House.
The head of US intelligence has defended the monitoring of foreign leaders as a key goal of operations.
The US is facing growing anger over reports it spied on its allies abroad.
It has also been reported that the National Security Agency monitored French diplomats in Washington and at the UN, and that it conducted surveillance on millions of French and Spanish telephone calls, among other operations against US allies.