"Foreign terrorist organisations like LeT use internet propaganda to radicalise and recruit individuals to wage violent jihad and spread terror," Neil H MacBride, US Attorney for the Eastern District of Virginia, told reporters here.
LeT is responsible for a number of terror attacks such as the 2008 Mumbai strikes which killed 166 individuals, including six Americans -- two of them from Virginia.
Referring to the conviction of Pakistani national Jubair Ahmad, a resident of Virginia, for supporting LeT, MacBride said the US would pursue all those who provide material support to terrorists.
This is the fifth case of home-grown terrorism in eastern district of Virginia that FBI has brought in the last year.
"It's a significant threat that we take very seriously," MacBride said.
Describing LeT as a "dangerous and deadly" foreign terrorist organisation, he said: "Over the years they have tried to change their name. And each time the US government has responded by classifying their pseudo or nick names as the foreign terrorist organisations."
Ahmad, 24, pleaded guilty before a US court of charges that he provided material support to LeT.
"This demonstrates our tireless commitment to disrupt and dismantle (what) we consider to be material support (to the terror outfits). We take radicalisation on the internet, on any firms of recruitment extremely seriously," said Brenda L Heck, Special Agent in Charge for FBI's Washington Field Office Counter-terrorism Division.