US Congress on Thursday held its first hearing on the Boston Marathon bombing, with witnesses calling for more resources for local law enforcement to combat homegrown terrorism.

At the House of Representatives Homeland Security Committee hearing, former senator Joe Lieberman, who appeared as a witness, said Congress should give more money to state and local law enforcement agencies to fight homegrown terrorists

"Particularly with homegrown terrorists, state and local law enforcers are in the best position to create the relationships within the communities that will allow them -- and have allowed them in numerous cases -- to stop terrorist attacks before they occur," said Lieberman. "They're simply not going to do it without funding."

At the same hearing, Boston Police Commissioner Edward Davis called for more technology such as surveillance cameras as well as special police units to provide tighter security for public events.

The hearing also explored why red flags risen before the attack failed to stop Tamerlan and Dzhokhar Tsarnaev, the brothers who were suspects of the April 15 bombing. Tamerlan was killed during a gun battle with police, and Dzhokhar was apprehended. The Russian authorities apparently warned the FBI about Tamerlan's extremist tendencies, but the FBI cleared him after interviewing him.

"The intelligence system we built after 9/11 failed to stop the Tsarnaev brothers," Lieberman said. "With your help, we must find out way and fix it."

The Boston bombing was the first successful terrorist attack against civilian targets in US homeland after 9/11 attacks in 2001. It killed 3 people, wounding over 200.