Yemeni security services arrested two European tourists after they illegally entered the Yemeni territory, the Interior Ministry said Tuesday. 'The two tourists were arrested in Sayon district of Hadramout province, some 900 km southeast of Sanaa, after the police found they have no visas,' the ministry said in a statement. The pair came from the Hadramout's district of Rumah and was planning to head for Sanaa, said the statement, adding 'the security authorities referred them to the immigration and passport department of Sayon for legal procedures.' The ministry did not specify how the two people entered Yemen. Yemen has been closely watching foreigners after a Nigerian man was appointed by the Yemeni-based al-Qaida group to carry out the failed Christmas Day attempt to blow up a U.S.-bound passenger plane last year. 