Washington, May 4 (IANS): In the wake of the Boston Marathon bombings, the US will tighten oversight to help ensure that foreign students seeking to enter the US have valid student visas, according to various media reports.

Effective immediately border agents at places like the airport or another entry point to the country will verify every international student making sure they have a valid student visa, ABC News reported.

If a student is no longer enrolled the information is updated in the student and exchange visitor information system called Student and Exchange Visitor Programme (SEVIS).

Under the new procedures, border agents will verify a student's visa status before the person arrives in the US using information provided in flight manifests. If that information is unavailable, border agents will check the visa status manually with the agency's national targeting data centre.

The measures come amid continuing investigation into the April 15 bombings that killed three and injured more than 260.
Three of surviving suspect Dzhokhar Tsarnaev's friends are facing federal charges on allegations of trying to hide evidence after the explosions.

One of the friends, Azamat Tazhayakov, 19, was allowed to reenter the US on a student visa even though he was no longer attending the University of Massachusetts Dartmouth, where Dzhokhar Tsarnaev also studied.

Congressional Republicans have questioned how the government has dealt with visa security issues, According to the Los Angeles Times.

In a three-page letter this week, Senator Charles E. Grassley asked Homeland Security Secretary Janet Napolitano for details about student visas and how Tazhayakov was able to reenter the US.

In a statement this week, the Homeland Security Department said that Tazhayakov entered the United States on Jan. 20 using a student visa with an expiration date of Aug 30.

"At the time of reentry there was no derogatory information that suggested this individual posed a national security or public safety threat."