RIYADH, May 25 (IslamOnline & News Agencies) - Saudi citizens must keep a close eye on their passports when traveling overseas to avoid problems faced by hundreds of countrymen following last September's anti-U.S. attacks, a Saudi official warned Saturday.

"Citizens should take care of their passports abroad exactly as they look after their money and personal valuables," deputy interior minister Prince Ahmad bin Abdul Aziz told Okaz newspaper.

"A passport is a very important document and should be accorded maximum attention," Prince Ahmad said, urging citizens to register with Saudi missions abroad.

Saudis traveling overseas should brace themselves for "more complicated [airport] procedures in the United States and Europe following September's attacks," he added.

Fifteen of the 19 hijackers in the September 11 terror attacks in the United States carried Saudi passports.

In the wake of the attacks, hundreds of Saudis, mostly students, were taken in for questioning by U.S. authorities. Many of them were detained for minor immigration or passport expiry violations.

A majority of them were released, but some remain in U.S. prisons awaiting trial.

The Saudi interior ministry on Wednesday cautioned Saudi nationals and expatriates living in the kingdom to beware of fraudsters who might use their identity documents in "criminal and terrorist acts."

“The interior ministry draws the attention of citizens and residents to the emergence of new methods ... of theft and fraud by individuals and sides outside" the kingdom, said a ministry statement quoted by the official SPA news agency. 

These sides, claiming to offer their potential victims money "under the guise of trade deals or humanitarian acts," request "photocopies of official documents and go on to use these documents and the names of their owners in acts of theft and fraud or in terrorist operations meant to harm Muslims and their home countries or countries of residence," it said. 
Advanced technology, chiefly the Internet and mobile phone text messages, have helped spread such methods, the ministry said, making it easier to use photocopies of IDs in "criminal and terrorist acts." 

The ministry urged citizens and residents to inform authorities of any suspicious contact by a party outside the kingdom.