Al-Qaeda claimed responsibility for an attack last week on a convoy of Belgian tourists in south-eastern Yemen that left two Belgians and two Yemenis dead, a news report said.
The al-Wasat weekly reported online on Wednesday that a leading member of the Al-Qaeda branch in Yemen claimed responsibility in a telephone call to the paper.
The claim has not appeared on radical Islamist websites that regularly post such messages from Al-Qaeda.
Security officials refused to comment on the claim.
"Recently, Al-Qaeda detainees endured inhuman treatment and many of them suffer now from various illnesses," the caller said, calling the attack "a response to the bad treatment of our brethren in jails of the Political Security (intelligence agency)".
A police official had said on Monday authorities had arrested four men believed to have shot dead two Belgian tourists in an attack on a convoy of tourists in Hadhramout, around 900 kms from the capital Sana'a last Friday.
Two female Belgian tourists and two Yemeni drivers were killed. Another Belgian tourist and three Yemenis were wounded.
The 15 tourists were travelling in four Land Cruiser vehicles in the Doan area of Hadhramout after visiting a historical site.
The attack was the second against Western tourists in Yemen within six months. In July, eight Spanish tourists were killed when a suicide bomber linked to Al-Qaeda rammed a car packed with explosives into their convoy in the central province of Marib.