The Scotland Yard has appealed for information from members of the public on the Sunday night assault on Lt Gen K S Brar, and described the four assailants as wearing dark clothing, long black jackets and having 'long beards'.
Stating that detectives were keeping an open mind on the motivation behind the attack, the police said in a statement on Monday that they were particularly keen to speak to people who assisted Brar and his wife after the attack on Old Quebec Street in central London.
No arrests had been made until last night, the police said.
"The four men are described as wearing dark clothing and long black jackets. They all had long beards. One of the men is described as younger and slimmer than the other three. They all fled in the direction of Oxford Street," the statement said.
"Detectives are keen to speak to anyone who was in the area at the time or who may have information about the incident. In particular they want to speak to those people who assisted the wife and the victim at the scene following the attack," it added.
According to Brar, a mobile phone had been recovered from the scene, which may help lead the police to the assailants. The police were also expected to go through CCTV footage from the area that has several cameras.
Recovering from the attack, Brar said he was now under heavy security in the London hotel, including personnel from Scotland Yard and the military attache from the Indian high commission. The hotel where he is staying had been cordoned off, he added.
"I did not have security in London but now there is a hell lot of security around me," he said. Brar, who has been on the hit-list of various extremists organisations for his central role in Operation Blue Star in 1984, said he was convinced that the assault was a bid to assassinate him.
Operation Bluestar was aimed at flushing out Sikh terrorists led by Jarnail Singh Bhindrawale from the Golden Temple, who was demanding a separate state for Sikhs called Khalistan.
A decorated soldier, Brar saw action in the 1971 war with Pakistan, and was among the first to enter Dhaka when the Indian army forced Pakistani army into surrender.
General A S Vaidya who was the army chief in 1984 planned the highly controversial Operation Bluestar. Vaidya was shot dead in Pune in 1986.