The United States of America will not allow our welcome to be abused by those who disguise themselves and their intentions

US Attorney General John Ashcroft

The new, web-based system will link the country's Immigration and Naturalization Service (INS) with more than 74,000 US schools and colleges and American consulates, Reuters news agency reported.

The system aims to replace a "slow, antiquated, paper-driven reporting system" and enable US authorities to "gain a measure of assurance that the students who are visiting our country are who they purport to be," Mr Ashcroft said.

America was shocked to discover that two of the hijackers on board planes that crashed into the World Trade Center in New York were granted visas to remain in the country.

Tough laws

"The United States of America will not allow our welcome to be abused by those who disguise themselves and their intentions," Mr Ashcroft said.

Atta's visa was approved six months after the 11 September attacks

Under the new system, which comes into force on 1 July, schools will be required to notify the INS within 24 hours if a student drops out or fails to attend classes.

A student's status must also be reported after each term and those wishing to study will have 30 days, not six months, to arrive at their place of study.

The system is in addition to extra laws imposed last month, when the INS introduced new measures requiring any foreigner wishing to study at a US university to have an approved student visa before taking any courses.

The INS had been under intense pressure from US Congress to implement the system following the revelations that Mohammed Atta of Egypt and Marwan al-Shehhi of the United Arab Emirates - thought to have flown two passenger planes into the World Trade Center - were granted visas.

US President George W Bush, who declared he was "stunned" by the incident, said at the time that the INS "needs to be modernised so we know who's coming... who's going out and why they're here".