FRANKFURT (AFP) - The German police said that part of the European Central Bank's (ECB's) premises in Frankfurt was briefly evacuated on Wednesday following the discovery of a suspicious letter.

The police in Frankfurt said that employees in the ECB's post department sounded the alarm on Wednesday morning when they saw black powder seeping out the letter.

One of the employees complained that she was feeling unwell after handling it and police and the fire brigade cordoned off the area as a precaution.

However, following an initial examination, no suspicious chemicals were detected. And the employee concerned said the symptoms had since disappeared.

As a result, the employees were allowed to return to their working places a short while later.

The black powder is now being chemically analysed, the police said.

There was no information regarding either the sender or the addressee of the letter.