Shimla, Sep 9 (IANS): The whereabouts of four trekkers from West Bengal, who went missing two days ago while trekking in Himachal Pradesh's Kullu, remained unknown on Friday and the search for them was stepped up, officials said.

Two of the six trekkers and one cook who went missing in the Kullu area reached Wachem, near Malana, on Thursday and informed about the incident, while four were missing, state Disaster Management Department Director Sudesh Kumar Mokhta told IANS.

They were on their way to capture Mt Ali Ratni Tibba (5458 m).

"A team of the Atal Bihari Vajpayee Institute of Mountaineering and Allied Sports has been deployed for the search operation," he said.

Some local trekkers and porters were also accompanying them. The SDM of Manali has coordinated the local rescue team, he added.

The missing have been identified as Abhijit Banik, Chinmoy Mondal, Dibash Das and Binoy Das.

The Kullu ranges are gorgeous, but they are also rugged, cold and inhospitable and no place for an inexperienced or ill-equipped trekker, say area tourist guides.

The scenic hills in the state attract thousands of foreigners for a range of activities like mountaineering, skiing, trekking, rafting and paragliding.