An earthquake of 5.7 magnitude on the Richter scale rocked Sikkim on Tuesday, killing at least two army personnel and two persons, including a girl.

Scores of important structures and buildings were also damaged in and around Gangtok.

State Chief Secretary N B Chingappa told reporters that two army personnel at Sherathang army camp, at an altitude of 12,000 foot in East Sikkim, were killed when they were hit by rolling boulders.

Further details were awaited as communication lines were disrupted, following the natural calamity.

The quake, which was felt at 6:25 am, sent people panicking in Sikkim and neighbouring hill sub-divisions of Darjeeling, Kalimpong, Kurseong and many parts of northern districts of West Bengal.

Reports reaching Gagntok said buildings of Raj Bhavan, headquarters of Sikkim Police, Enchey monastery, State Secretariat, State Bank of India [Get Quote] office at Zero point and many others at Rangpo and Bardan in East Sikkim were damaged. Many important roads linking Gangtok were also damaged, the reports added.

DIG (Range) A Sachdeva said most of the damage had been reported from East Sikkim.

Reports of earthquake at Darjeeling, Kurseong and Kalingpong in neighbouring West Bengal were also received. A Siliguri report said the hill sub-divisons were rocked Tuesday morning sending the people out of home in panic. There was, however, no report of any casualty.

Minor tremors were also felt in Siliguri, Cooch Behar and Maldah regions of north Bengal.

Sachdeva said in east Sikkim two people -- a girl and a man -- were injured in the quake. The girl sustained injuries when a portion of roof fell on her during sleep at Ranipool. The man was injured when a boulder hit him.

An emergency meeting of the disaster managemet group comprising army, police and civil officials was going on to chalk out the evacuation. State Urban Department and Public Works Department officials were asked to find out about damaged buildings and report to the state chief minister by Wednesday for emergency evacuation.

Ground floor and first floor of the six-storey Secretariat building were damaged. However, the building was declared safe. An army barrack at Bardang was also damaged along with Sikkim Manipal Medical College.

Meanwhile, Buddhist lamas in various monasteries started special prayers to pacify the "nature god". All the lamas and priests of the Enchey monastery were evacuated after cracks appeared in the 150-year-old monastery.

Reports of quake in the neighbouring Bhutan also received.

Government sources said the people were asked to keep calm and not to panic.

There was no report of any damange in north, west and south Sikkim.