The U.S. Homeland Security Department has ordered border agents to check whether every international student who arrives in the county has a valid student visa- a new security measure put in place from immediate effect in the wake of the recent Boston bombings.

David J. Murphy, a senior official at the U.S. Customs and Border Protection, passed on the order, Thursday, after the Obama Administration realized that Azamat Tazhayakov (a friend of the surviving suspect in the Boston Marathon bombings, Dzhokhar Tsarnaev), had left the U.S. in  December and was allowed to return, Jan. 20, without a valid student visa.

Apparently, he submitted an expired student visa and a letter of enrolment from the University of Massachusetts, which the department could not verify as the information had not been updated. The officials later discovered that the university had reported to the department that Tazhayakov's enrolment had ended on Jan. 4.

In order to avoid such security lapses, the border agents at the airports will now have access to Homeland Security Department's Student and Exchange Visitor Information System (SEVIS), which contains latest information on colleges and universities with foreign students and their current enrolment status.

Security officials did not have access to this database when Tazhayakov returned to the country. Under existing procedures, border agents can verify a student's status in SEVIS only when the person has been referred to a second officer for additional inspection or questioning.

Tazhayakov was not sent to a second officer when he arrived.

Under the new procedures, all border agents will be able to access SEVIS. Plus, they will verify a student's visa status before he/she arrives in the U.S. with information provided in flight manifests. If that information is unavailable, they will check the visa status with the agency's national targeting data center.

Tazhayakov and a second Kazakh student were arrested on federal charges of obstruction of justice, Wednesday, for allegedly covering up the evidence of Tsarnaev's role in the bomb blasts.

They tried to get rid of a backpack containing fireworks linked to Tsarnaev. A third student was also arrested for lying to authorities.