Four youths with suspected terror links who were allegedly conspiring to strike in the mela area were held by a joint team of Delhi Police Special Cell and Uttarakhand police on Tuesday night from Manglour town in Haridwar district.
The state government asked all mountaineers to return to their base camps following heavy snowfall and blizzards in the region.
Lakhs of devotees on Thursday thronged the Ganga banks in Haridwar, including Har Ki Pauri, to take a dip in the sacred river on the occasion of Makar Sankranti which also marks the first major bath of the ongoing Ardhakumbh mela in Uttarakhand.
A private helicopter, hired along with two other choppers for the visit of Bharatiya Janata Party chief Nitin Gadkari and his family, crashed in Ladpur jungles on Sunday barely hours after the group had got down at the airport, leaving the pilot and an engineer seriously injured.