"But they are demands that cannot be met by the Austrian side because they concern the release of prisoners in Tunisia and Algeria."

 

Among the prisoners the group wants released is former soldier Amar Saifi, known as El Para, or the The Paratrooper, a leading figure in the Salafist Group for Preaching and Combat (GSPC), which in 2006 allied itself to al-Qaeda.

  

Saifi, who was allegedly behind the 2003 abduction of 32 European tourists, was captured in Chad and returned to Algeria, where he is awaiting trial.

 
A statement posted on a website attributed to the group gave the Austrian authorities three days to comply, starting at midnight on Thursday.
 
"The state of Austria is responsible for the lives of the two hostages in the event of the expiration of the time-period and not responding to our demands," said the statement, which included six photographs purportedly showing the two hostages.
 
Search on
 

The Austrian press has identified the two hostages as Wolfgang Ebner, 51, and Andrea Kloiber, 44.

 

Their exact whereabouts are unknown, with the authorities in Algeria and Tunisia say they are in the other's territory.

 
Vienna said this week that it was doing all it could to find the two and that an extensive search was under way in an area the size of Austria.
 
Relatives reported the pair missing when they did not return from a holiday to Tunisia on March 1.
 
The two were last heard from on February 18 and failed to make a planned phone call to Ebner's son on February 25.
 
Austrian media identified Ebner as a tax consultant from the town of Hallein, and said Kloiber is his girlfriend.
 
Gaza link
 
The authorities began a search for the two tourists after Al Jazeera's Arabic channel aired an audio tape, said to be from al-Qaeda's North African branch, which linked the abduction of the consultant and nurse to the violence in Gaza.
 
It said the man and woman were taken on February 22 and that they were in good health.
 
The tape also warned Western tourists to stay away from the Maghreb region of North Africa of which Tunisia is a part.
 
"We tell Western tourists flocking to Tunisia for leisure at a time when our brethren are being slaughtered in Gaza by the Jews with the complicity of Western states ... the apostate Tunisian state is not able, and will not be able, to protect you," the voice on the tape warned.
 
Tunisian denial
 
The Tunisian government said it had carried out "intensive search operations" but there was no proof of the two tourists being in the country.
 
It said the Austrians were last heard of crossing the Sahara desert in a direction that would have taken them out of Tunisia.
 
Meanwhile, the US state department issued a warning to travellers to Tunisia in the wake of the kidnappings.
 
"Al-Qaeda Islamic Maghreb is designated as a terrorist organisation by the United States, and its presence in North Africa presents potential dangers to travellers," the statement said.