(Corrects to "land and air" from "sea and air")

TUNIS, March 10 (Reuters) - Tunisian authorities have launched a hunt for two Austrian tourists missing and believed kidnapped by al Qaeda, but there is no proof they are still in Tunisia, the north African country's government said on Monday.

"The authorities have begun carrying out intensive search operations by land and air," a government statement said, adding the two were last heard of crossing the Sahara in a direction that would have taken them beyond Tunisian borders.

"Until now there is no element that proves that the two Austrian citizens are in Tunisian territory or that they were kidnapped inside Tunisian borders," it added.

Al Qaeda's North Africa wing said on Monday it was holding two Austrian tourists it had abducted in Tunisia on Feb. 22. (Reporting by Tarek Amara; Writing by William Maclean; Editing by Ibon Villelabeitia)

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