The Centre on Thursday sought a report from the West Bengal government on alleged "serious security lapses" during the visit of BJP president J P Nadda to the state, officials said.
The Union Home Ministry's communication to the West Bengal government came after BJP state unit chief Dilip Ghosh wrote to Union Home Minister Amit Shah on Wednesday.
In his letter, Ghosh alleged that a "mob" of over 200 people with sticks and bamboos were demonstrating raising black flags in front of BJP's state unit office in Kolkata.
He also claimed that some of the protesters climbed on cars parked outside the party's office and raised slogans, and the "police did not intervene to stop them and casually allowed them to come within a close perimeter of Nadda ji's vehicle".
The Ministry has sought a report from the West Bengal government on the alleged "serious security lapses" during the BJP president's visit, the circumstances and what action has been taken on it, a Home Ministry official said.
In his letter on Wednesday, Ghosh had also said, "Today during his different engagement in Kolkata, it was observed that there were serious lapses on security arrangements, purportedly due to negligence and/or casual approach of the state police department."
Nadda is on a two-day visit to West Bengal, where assembly election is due next year, and on Thursday, stones were hurled at his convoy, when it was on its way to Diamond Harbour in West Bengal''s South 24 Parganas district from Kolkata.