Lashkar-e-Taiba (LeT) bomb-maker and terrorist Abdul Karim Tunda was Tuesday slapped by a man who claimed to be a member of a group called Hindu Sena while he was entering the Patiala House district courts here, police said.
The attacker and his accomplice were detained.
Tunda was arrested by Delhi Police last week from the India-Nepal border.
Shiv Kumar Raghav, 40, slapped Tunda at around 3.50 p.m. when the terrorist was being taken to a court after three days of police custody.
Along with Raghav, another member of Hindu Sena, Vishnu Gupta, was also detained by police just after the attack.
"Tunda is a traitor, he should be hanged," Raghav was shouting after he slapped Tunda and was detained by police.
Police personnel have been reinforced outside Patiala House court after the incident.