With a manhunt underway for radical Sikh preacher and Khalistan sympathiser Amritpal Singh in Punjab, Haryana has intensified checking of vehicles along the border with the neighbouring state.

Punjab Police on Saturday launched a major crackdown against Amritpal and suspended internet and SMS services till Monday noon. It has arrested 78 members of 'Punjab Waris De', an outfit headed by him.

At the Shambhu border with Punjab, Ambala police have been put on high alert, officials said on Sunday.

Additional checkpoints have been set up and a large number of police personnel have been deployed there, they said.

In some other districts too, including Kurukshetra, Kaithal and Sirsa, which share borders with Punjab, police are maintaining strict vigil and have intensified checking of vehicles, they said.

CIA-1 incharge of Ambala police Harjinder Singh, who was present at the Haryana-Punjab border near Shambhu, said the situation is normal and peaceful but police are maintaining a vigil.

In Punjab, security forces conducted flag marches at several places in the state, including Amritsar, Jalandhar and Ludhiana.

Dubai-returned Amritpal was last year anointed the head of 'Waris Punjab De', which was founded by actor and activist Deep Sidhu who died in a road accident in February last year.

Last month, Amritpal and his supporters, some of them brandishing swords and guns, broke through barricades and barged into Ajnala police station on the outskirts of Amritsar city, and clashed with police for the release of one of his aides. Six policemen were injured in the incident.

Punjab Police filed an FIR on February 23 in connection with the incident.