Security measures at Switzerland's nuclear installations must be bolstered in case of a plane or sabotage attack, according to the Swiss Federal Nuclear Safety Inspectorate. The warning comes almost a fortnight after three passenger planes smashed into the Pentagon and World Trade Centre in the United States.
Switzerland and its neighbour, Germany, are the only two countries to impose measures to protect nuclear sites against a plane impact, a statement from the inspectorate said on Friday.
Last week's terrorist attacks in the US pushed defence issues to the top of the political agenda and prompted governments to step up security at public places, such as airports, and at strategic sites, such as nuclear power plants.
The inspectorate, which is responsible for supervising and assessing Swiss nuclear installations, says that buildings housing reactors have to be built to withstand the impact of a military plane with a mass of 20 tonnes coming at a speed of 774 kilometres per hour.
The protection systems at the Mühleberg and Beznau nuclear plants for example, which were built in the 1970s, were bolstered 1989 and 1992 respectively. The inspectorate said they could withstand an immense attack for ten hours without any human intervention.
Didier Vallon, deputy head of information for the Swiss airforce, said that controls are in place to shoot down any suspect planes flying dangerously close to nuclear or military installations.
"Planes are allowed to fly over these buildings but they must remain at a certain flight level. The skyguides responsible for air traffic control need to inform the authorities about any transgression. An order from the transport minister would then allow the Swiss airforce to shoot the plane down," Vallon told swissinfo.
However, it would not take a plane travelling at high speeds long to reach its target. Vallon admitted that the reaction process was slow and that not much could be done to stop the plane from reaching its target.
Vallon explained that Switzerland is still in peacetime despite America's declaration of war on those responsible for last Tuesday's assaults. As such, only hidden military and nuclear installations have additional protection.
"We could send aircraft into the air very quickly but during weekends and the night, it is completely different because we are in peacetime." Vallon said.
The nuclear safety inspectorate said that not all operating nuclear stations are prepared to completely withstand the consequences of an attack similar to the ones on the Pentagon and twin towers.
The inspectorate said it was possible that combustible elements in stock or the cooling system might be affected and radioactive elements escape in the case of such an assault.
Those in charge of all nuclear stations have been requested to review plans to protect their installations in case of a plane attack, and the inspectorate said it was exploring additional security measures.
swissinfo with agencies