Washington: In a dangerous sign that Pakistan-based Lashkar-e-Taiba (LeT) has expanded its tentacles in the United States, federal prosecutors on Friday announced to have arrested a New Yorker who was about to catch a flight to Pakistan to join the terror group.

While in Texas, the FBI charged a teenager with using social media to recruit people on behalf of the LeT. Jesus Wilfredo Encarnacion (29), was arrested Thursday night at John F Kennedy International Airport (JFK Airport) as he was about to board an international flight with Pakistan being his final destination.

"Encarnacion allegedly attempted to travel to Pakistan to join a foreign terrorist organization and conspired with another individual to provide that organization with material support," said Assistant Attorney General John Demers.

Encarnacion, a.k.a. "Jihadistsoldgier", "Jihadinhear", "Jihadinheart" and "Lionofthegood," plotted to travel to Pakistan to join and train with LeT, which is infamous around the world for perpetrating the lethal 2008 Mumbai terror attacks and other atrocities, said US Attorney Geoffrey Berman.

A Manhattan resident, Encarnacion not only express a desire to "execute and behead people," he scheduled travel and almost boarded a plane so he could go learn how to become a terrorist, FBI Assistant Director-in-Charge William Sweeney Jr.

In the southern state of Texas, Michael Kyle Sewell, 18, was charged by the FBI with using social media to recruit people on behalf of LeT and send them to Pakistan for terrorist training.

The arrest of the New Yorker and the charges against the Texas teenager who do not appear to be of South Asian origin as has been the case in previous such arrests has set the alarm bells ringing among the law enforcement agencies in the US.

The arrests have thrown the spotlight on issues of homegrown terrorism and radicalisation of American youths, a situation that authorities have dreaded post Mumbai-terrorist attack.

Based out of Pakistan, the LeT is a UN and US designated global terrorist organisation and has carried out several terrorist attacks inside India, including the Mumbai terrorist attack in 2008 that took the lives of more than 160 innocent people including several Americans.

"These organisations are using the internet and social media to appeal to the most barbaric impulses in people, and train them to kill," Sweeney Jr. added.

According to NYPD Police Commissioner James O'Neill, one of Encarnacion's stated motives for travelling overseas was to get the training and experience he believed he needed to someday return to the United States and carry out attacks. Meanwhile, Sewell, who encouraged and recruited an individual to join the LeT hails from Fort Worth city and met the man.

"Sewell allegedly used social media to recruit and encourage an individual to travel overseas to join a foreign terrorist organization and conspired with that person to provide material support to that organisation," Demers said.

According to the criminal complaint, Sewell provided the co-conspirator with contact information of an individual he believed could facilitate the travel to Pakistan. Unbeknownst to Sewell and his partner, the facilitator was an undercover FBI agent, the federal prosecutors said.

Sewell had even coached the co-conspirator on how to convince the facilitator that he was sincere in his desire to fight for the LeT, they added. The teen also contacted the facilitator to vouch for the co-conspirator's authenticity and told both of them that he would kill the coconspirator if he turned out to be a spy.

The co-conspirator then contacted the facilitator and made arrangements to travel to Pakistan, the criminal complaint said.