A New Delhi police spokesman said the Intelligence Bureau recently intercepted a telephone conversation between suspected Lashkar-e-Toiba militants who were discussing plans to carry out a terror strike in the capital.
Karnail Singh, deputy commissioner of police, Special Branch, said police have also informed their counterparts in nearby Uttar Pradesh.
"Security was tightened at all important government and private installations, which could be on the probable target list of militants," Singh said. "Searches were carried out at guesthouses and hotels, and checking of all vehicles along the border was intensified."
He said the strength of security personnel at Indira Gandhi International Airport, Delhi Metro and other railway stations had been increased.