A young man Saturday smeared ink on Aam Aadmi Party (AAP) leader Yogendra Yadav's face after springing from behind him at a party rally here to mark International Women's Day.
Yadav later requested police not to take any action against the 35-year-old attacker who was identified by police as Sagar Bhandari, a native of Assam.
Yadav also wrote a letter to Delhi Police that said: "I would wish to request you that no case be registered against that misguided person. If he is detained, he may please be released. If possible, I would like to get an opportunity to speak to him."
Bhandari, wearing the trademark white AAP cap, leaped onto the stage where Yadav was seated and talking to the media.
Before Yadav or the AAP members around him could realise what was happening, he repeatedly smeared ink on Yadav's face, temporarily blinding him.
It took four or five seconds before others came to Yadav's rescue, pushing away the attacker who was then roughed up. Police quickly intervened and took him away.
A police officer said Bhandari was apparently a disgruntled AAP worker and worked at the party office in the Shalimar Bagh area.
Yadav, the AAP candidate from Gurgaon in Haryana for the Lok Sabha elections, was clearly stunned.
"I was talking to you when this person came from behind and put ink on my face," he told journalists near Jantar Mantar where the meeting was held. "I did not see him... I mean how could I see him."
He added: "When you take on powerful forces in this country, one must be ready to pay a price. May God forgive this man (attacker)."