Aizawl/Kohima, June 22 : A moderate earthquake, measuring 5.5 on the Richter scale -- and the second in 12 hours, shook Mizoram and other adjoining northeastern states bordering Myanmar on Monday, damaging many buildings and important installations, officials said. According to police, there was no report of loss of life. However, at least 31 structures, comprising houses, government and non-government buildings, police stations, churches and community halls, developed cracks due to the tremor. An IMD official said that the tremor hit eastern Mizoram's Champhai area, adjoining Myanmar, and several other parts of the mountainous state at 4.10 a.m. on Monday morning. The quake, that lasted for several seconds, was at 20 km depth. Mizoram had also experienced earthquakes measuring 5.1 and 5 on the Richter scale on Sunday afternoon (at 4.16 p.m.) and Thursday night respectively. Prime Minister Narendra Modi and Union Home Minister Amit Shah talked with Mizoram Chief Minister Zoramthanga and offered the Centre's help in view of the early morning quake. "Two earthquakes rocked Mizoram within 12 hours. Damage assessment has been undertaken by concerned MLA and district administration. Fortunately, no casualties have been reported so far. Thanking PM and Home Minister for their assurance of support," Zoramthanga said in a tweet. Mizoram police, quoting the local people, said that the tremors jolted many parts of East Tuipui assembly constituency in Champhai district. "Local people said an aftershock was experienced after half an hour. More than 31 houses, buildings, church and community halls developed cracks after the tremor," a police official said. According to the local people, the Monday morning quake seems to be the strongest one in Mizoram in the recent past. The IMD official said that a low intensity quake measuring 2.8 on the Richter scale also shook several parts of Nagaland at 12.40 p.m. on Monday. The depth of the quake was at 6.6 km. There was no report of any damage or casualty in the Nagaland tremor. Champhai district Deputy Commissioner Maria C.T. Zuali, after a preliminary assessment, said that 31 buildings and important installations including churches, police stations, immigration check posts and water reservoir were damaged under Champhai and Khawbung rural development blocks. Some roads and tourist lodges were also damaged. A call centre has been set up at the Deputy Commissioner's office. "Officials have rushed to the concerned villages to assess the damages in the field," the Deputy Commissioner said. Seismologists consider the mountainous northeast region as the sixth major earthquake-prone belt in the world. In 1897, a Shillong-epicentre quake measuring 8.2 on the Richter scale had hit the area. In 1950, an earthquake measuring 8.7 on the Richter scale had altered the course of the Brahmaputra river. /IANS