Local authorities were using loudspeakers to announce to residents in the border villages to leave their homes and villages and move to safer zones.
The authorities have ordered the closure of schools and other institutions in the border belt.
Punjab’s border districts include Amritsar, Gurdaspur, Tarn Taran, Ferozepur, Faridkot, Abohar and Fazilka.
Informed sources said the Border Security Force (BSF) was mobilising its troops and strengthening the security along the border belt.
Punjab shares a 553-km border with Pakistan.
Punjab Chief Minister Parkash Singh Badal has called an emergency meeting of the cabinet on Thursday evening.