Switzerland says it will shoot down any unauthorised aircraft flying over Davos during the upcoming World Economic Forum (WEF) summit.
The measure is one of several taken to ensure security for the global business and political leaders taking part in the annual summit, Swiss officials said.
The measure, which will take effect between 23 and 28 January when the economic forum is in progress, is designed to ensure complete control of the air space above the Alpine resort of Davos.
But Oswald Sigg, a spokesman for the Swiss defence ministry, said that "it was only to be used as a last resort".
"All aircraft that comply with air control regulations may fly over Davos," he said.
The conditions under which the army may shoot down a plane or hot air balloon have not yet been specified.
"According to the law, the head of the Swiss Air Force has the authority to order fire," Sigg explained.
Switzerland's political leaders would be informed of such a decision.
The government is set to ratify the security measure on January 15. The Civil Aviation Office has already given its backing.
Swiss army chief Christophe Keckeis said the measure was based on a 1984 ruling that outlines conditions under which air traffic should be limited.
It reportedly states that firing on a civil aircraft is permitted if it flouts traffic control instructions. Such a measure has never been implemented.
In another move to ensure the security of WEF delegates, Swiss authorities have barred around 100 people from travelling to Davos.
The bans have been imposed on foreign activists known to have committed, or believed to be preparing, "acts of violence", according to Jean-Luc Vez, the head of the Swiss Federal Police Office.
Vez said he believed the majority of protesters had peaceful intentions, but warned that those who committed acts of violence would be identified and isolated.
swissinfo with agencies
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