Armed men on Friday opened fire in the Delhi Cantonment area injuring a jawan, who was guarding the gates of the 4 Engineers Regiment Office, an army spokesman said.
Police and the army have still not confirmed whether it was a terrorist attack and said investigation and search was on.
The army has cordoned off the entire area and the police have been informed, the spokesman said.
He said the incident occurred around 1615 IST, when a black Toyota Qualis came and stopped outside the main gate of the regiment office on Thimayya Road.
When the jawan on sentry duty asked him not to halt in front of the gate, the driver of the vehicle went back about 200 yards.
Soon the vehicle came back and the driver fired two bursts, apparently from an automatic rifle, he said.
The jawan, who was hit on the leg by a bullet, retaliated, but the vehicle sped away.
The spokesman said the sentry was immediately rushed to the Base Hospital.
Quoting preliminary reports, he said there were apparently two persons in the Qualis.
While the driver was bearded and wore a black dress, the other person had his face covered, he added.