Residents of the German city of Hanover have been told to keep away from windows and avoid waving at President Obama when he visits later this month - incase they are shot by trigger-happy American secret service agents.

Police have issued flyers to nearly 2,000 people living near the Congress Centre due to be visited by Obama on April 24.

He will meet there with Chancellor Angela Merkel for the Hanover Messe, an industrial technology fair.

President Barack Obama (right) will meet with Chancellor Angela Merkel (left) for the Hanover Messe on April 24 amid high security

Police have issued flyers to nearly 2,000 people living near the Congress Centre due to be visited by Obama on April 24

As well as keeping away from windows and waving, residents expecting visitors that weekend will have to register them with police a week beforehand.

People working in shops lying within the security area will also have to register.

'The elegant zoo district is being turned into a fortress!' said the Bild newspaper about the security operation, which also includes removing bicycles from streets the presidential motorcade will pass along and turning off mobile phone transmitters at unspecified times.

Trains and bus lines will be halted all around the security zone, manhole covers welded shut and police snipers placed on rooftops.

All overseas visits by American heads of state are traditionally surrounded with extra security, but the terror attacks in Paris last year and Brussels last month have made this excursion even more fraught with danger for the authorities.

American secret service agents are already in Hanover (pictured) plotting the security arrangements for the visit. Just where he will be staying remains top secret

It added: 'The residents living in the Zoo quarter will be closer to the U.S. President than anyone in Hanover.

'But nevertheless, it will be virtually impossible to get even a glimpse of the most powerful man in the world.'

Although the police letter does not specifically say residents risk taking a bullet if they wave from a window at the president, no-one is left in any doubt that that is the message authorities are sending.

'Please understand that security forces operate under special alert during the visit of the US president,' police added in their security note.