Punjab Police sources say the three terrorists, along with their handler from Jammu and Kashmir, had crossed the Banihal tunnel in the neighbouring state late on Tuesday, April 5 night.
The terrorists, as per the alert, were moving in a grey-coloured Maruti Swift car, a senior Punjab Police officer said here.
The Punjab Police has warned that the suspected terrorists could have entered Punjab, which shares its northern border with Jammu and Kashmir.
Security and intelligence agencies in Delhi claimed the terrorists could target Delhi, Mumbai or Goa.
Punjab has witnessed two major terror attacks in the past nine months.
Suspected Pakistani terrorists attacked the Pathankot Indian Air Force base on January 2 and killed seven security personnel.[Terrorists may target Delhi, Mumbai and Goa, says Intelligence report]
On July 27 last year, three suspected Pakistani terrorists attacked Dinanagar town in Gurdaspur district leaving seven people dead.
Both attacks took place in areas of Punjab bordering Jammu and Kashmir.