Gangtok, Sep 19 (IANS): A day after a powerful earthquake of 6.8 magnitude ravaged the Sikkim-Nepal border, killing at least 30 in India, the army Monday was busy carrying out rescue and relief operations.

According to sources, about 50 army columns in small teams were deployed across Sikkim, Siliguri, Binaguri and local units around Gangtok for rescue operations on a war footing.

The columns comprised medical teams with first aid, engineer detachments and relief and rescue units.

About 10 army combat engineer columns were rushed with equipment for opening major roadblocks on Siliguri-Gangtok.

Apart from the army, the Border Roads Organisation (BRO) has also been mobilised for restoring normal traffic on NH-31A which connects Sikkim with the rest of the country.

"Sikkim has been cut off from the rest of the country with the national highway 31-A blocked in at least eight places following heavy mudslides," said G. Anandan, district magistrate, Sikkim East.

The high-intensity quake was followed by two aftershocks and had its epicentre on the Sikkim-Nepal border. The impact of the temblor was so powerful that several army buildings had developed cracks.

"As many as 25 concrete bridges were damaged between Siliguri and Gangtok on the 120 km long national highway 31-A. The Sikkim secretariat also developed cracks," Anandan said.

Meanwhile, the Indian Air Force (IAF) has rushed five cargo planes to the northeast with relief material and personnel. Even as army deployed in the region works for the relief and rescue, incessant rains are hampering the operations.

The tremors were also felt in Assam, parts of West Bengal, Jharkhand, Bihar, Uttar Pradesh, Rajasthan and Delhi.