The US government is to conduct background checks on all applicants for student visas who come from seven countries considered to be sponsors of terrorism.
Government officials and universities will also be required to monitor the movements of all foreign students in the US.
Government bureaucrats had approved student visas for two men to attend a Florida flight school - six months after they died when they were among the hijackers of the planes involved in the terrorist attacks on September 11. The men had applied for the visas before the attacks.
Under the new rules, student visas will not be issued unless the sponsoring university or college confirms that a student has been accepted for enrolment. The institutions will also have to report when and if the student arrives as scheduled.
Detailed background checks will be performed on all student visa applicants from seven countries considered to sponsor terrorism: Cuba, Iran, Iraq, Libya, North Korea, Sudan and Syria. About 4,000 students from those nations were enrolled last year at US universities and colleges.
The Bush administration is also considering barring some international students from fields, including nuclear technology, chemical engineering and biotechnology, which could be used to develop weapons of mass destruction.