"A citizen with Swiss-Iraqi double nationality died during an incident (in Baghdad) last Tuesday," Foreign Ministry spokesman Ivo Sieber said.

The name of the dead man was not released.

His brother, who was travelling with him, told Swiss authorities their car had been stopped by US soldiers and that the victim died from a gunshot, Mr Sieber said.

There were no details about where the gunshot came from or who fired it, and Switzerland has asked for more information from the US embassy in Iraq and from the State Department and Pentagon in Washington.

It also asked for a police report on the incident from the Iraqi Foreign Ministry.