Seven more bodies were found in the quake rubble, taking the death toll in the calamity in Sikkim to 60 as rescuers on Wednesday struggled to reach the devastated areas where "heavy casualties" were feared.

Official sources said six bodies were found in East Sikkim and one in North Sikkim, where the 6.8 magnitude temblor was epicentred.

Fresh landslides triggered by heavy rains were reported in the worst-affected areas of Mangan, Lachung, Lachen and Sighthan areas of North Sikkim last night.

The landslides and landslips along the 60 km stretch between Gangtok and Mangan along NH31A, the lifeline of the mountain state, was affecting rescue operations in the higher reaches in the mountains, army sources said.

Army sources said a 8-10 km stretch at Tung, which is 16 km off Mangan, had caved in impeding rescue operators from reaching worst-hit Chungthang.

Sikkim director general of police Jasbir Singh said Border Road Organisation personnel were deployed to clear the highway.

District collectors have been asked to reach Mangan, Lachen, Lachung and Chungthan, rendered inaccessible by the landslides, immediately by air as more bodies are feared to be trapped in under quake debris.

"Heavy casualties are feared in these areas," he said.

Indian Air Force continued recces in North Sikkim, where relief material was airdropped yesterday.

Meanwhile, the bus missing with 24 passengers and crew was rescued from Tung last night.

Army, NDRF and disaster management personnel walked to Tung, between quake epi-centre Mangan and Chungthang and rescued the people in the bus last night. However, one person in the bus had died, official sources said.

AICC general secretary Rahul Gandhi has, meanwhile, reached Bagdogra Airport in West Bengal on way to Gangtok, the Sikkim DGP said.

Inclement weather delayed his arrival by about two hours.

Gandhi is scheduled to visit worst-hit Chungthang during the day, he added.