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By Inal Ersan

DUBAI, March 16 (Reuters) - A leading Sunni Muslim cleric urged al Qaeda's North Africa wing on Sunday to free two Austrian hostages it abducted in Tunisia more than three weeks ago.

"I urge you in the name of God, Islam, the Koran and the interest of the (Islamic) nation to free the two hostages for the sake of the dignity of this religion," Egyptian scholar Youssef al-Qaradawi said on Al Jazeera television.

The captives, Andrea Kloiber, 43, and Wolfgang Ebner, 51, went missing while on holiday in Tunisia last month and the Algerian-based Al Qaeda in the Islamic Maghreb said it seized them on Feb. 22.

The group has threatened to kill the two tourists if Vienna does not secure the release of some of its prisoners in Tunisia and Algeria.

In his televised message, Qaradawi told the captors that Islam bans taking innocent people as hostages to apply pressure on others.

"They have no guilt. They are innocent civilians used to punish others or apply pressure on them. In Islam people are only responsible for what they do individually," said Qaradawi, who is based in Qatar.

Austria earlier on Sunday it had won more time to try to secure the release of two Austrian tourists being held hostage by al Qaeda in Mali's remote northeast Kidal region.

Al Qaeda had set a deadline of midnight on Sunday for its demands to be met, but Austria said this had been extended for an unspecified amount of time and that an Austrian diplomatic envoy has been working for the release of the tourists.

"I urge the captors, our brothers and sons, to let them go," he said. "Austria has a good stance on Islam."

Qaradawi heads an international body of Islamic scholars and his opinions are widely respected in many Muslim countries.

Britain last month said it had refused a visa to Qaradawi, accusing him of justifying terrorism. The United States has also denied him a visa.

Although Qaradawi had condemned al Qaeda's Sept. 11, 2001 attacks on the United States, he has supported Palestinian suicide bombing and attacks on coalition forces in Iraq as acts of resistance against occupation forces. (Reporting by Inal Ersan; Editing by Caroline Drees)

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