The security adviser to the Andhra Pradesh government has started a probe into Wednesday's attempt by the People's War to kill Chief Minister N Chandrababu Naidu.

S Subramanyam, one of the founders of the Special Protection Group, will try to pinpoint the security lapses and intelligence failure that led to the attack on Naidu, who gets 'Z' category protection.

Subramanyam, a retired Indian Police Service officer who had a stint in the Intelligence Bureau, has been asked to suggest measures to strengthen the security cover for the CM and other VIPs.

Additional Director-General of Police (CID) M L Kumawat, who was in Tirupati at the time of the incident, has also taken up investigations.

DGP S R Sukumara has also asked Deputy Inspector-General of Police, Anantapur range, A V Narayana, to probe the security lapses.

Sukumara held a meeting with police officials in Hyderabad to review the situation.

Meanwhile, Naidu, who returned to Hyderabad by a special aircraft from Tirupati, has been advised by doctors to take complete rest for three days.

Police kept away scores of Telugu Desam Party leaders and well-wishers who converged near the CM's residence at Jubilee Hills.

Irrigation Minister Kadiam Srihari and TDP spokesperson and Member of Parliament Ummareddy Venkateswarlu said Naidu enquired about the condition of Information Technology Minister B Gopalakrishna Reddy and the two legislators who were hurt in the attack.

Governor Surjit Singh Barnala called on Naidu.

Health Minister Dr Kodela Sivaprasada Rao said the condition of Naidu, who suffered a hairline fracture on his collarbone, was stable. "Everything is okay, except some problem with his right shoulder."

In Hyderabad and elsewhere in the state, TDP leaders took out rallies and processions condemning the incident.

The party, which gave a call for observing the birth anniversary of Mahatma Gandhi as "peace and non-violence day", organised prayer meetings and pujas at temples and other places of worship.

Bharatiya Janata Party and Congress leaders participated in a meeting at Hyderabad.

Leader of the Opposition Dr Y S Rajasekhar Reddy, who reached Tirupati on Thursday morning, began a silent protest in the temple town demanding foolproof security for all politicians.