JAKARTA , Indonesia ( CNN ) -- Another strong earthquake rocked Indonesia early Thursday as the Southeast Asian nation was reeling from an earlier jolt that killed more than 200 people . A resident stands next to building that collapsed onto a car in Padang , Indonesia , on Wednesday . The 6.8 magnitude quake Thursday hit southern Sumatra at 8:52 a.m. local time ( 0152 GMT ) , the Pacific Tsunami Warning Center said . Wednesday 's earlier quake was 7.6 magnitude . At least 236 people are dead and more than 500 injured , the Indonesian Social Ministry 's Crisis Center said Thursday . It said it had little information on the missing and feared the death toll would climb into the thousands . The second quake was on a smaller scale than the first , said meteorology official Fauzi , who uses only one name . There were no damage reports yet . Indonesian Health Minister Siti Fadilah Supari expected `` the casualties and the damage of this earthquake to be bigger than the 2006 Yogyakarta earthquake , given the intensity and the spread of the damage . '' The magnitude-6.3 Yogyakarta quake in central Java in May 2006 killed more than 5,000 people , triggered fears of an eruption of a nearby volcano and caused significant damage to a 9th century Prambanan temple . Thousands may be trapped by collapsed buildings and houses , Rustam Pakaya , the head of the Health Ministry 's crisis center , told CNN on Wednesday . State-run Antara news agency cited Pakaya as saying he had received reports that part of a hospital had collapsed and that people were buried under the debris . The temblor struck around 5 p.m. , about 33 miles ( 53 kilometers ) from Padang , the capital city of West Sumatra and home to more than 800,000 people . The quake caused widespread power and phone outages , making it difficult to assess damage . Aid agencies kicked into gear to help those in need . `` We had aid ready because this area of Indonesia is susceptible to this type of tragedy , '' said Jane Cocking , humanitarian director for Oxfam . `` Communications with the quake-zone are difficult and we are hoping for the best but having to plan for the worst . '' `` The situation is quite devastating , '' said Amelia Merrick , the operations director for World Vision Indonesia . `` Bridges have gone down , phone lines are in total disrepair . It 's difficult for us to assess the situation , '' she said . The organization had said it would send assessment teams to the area Thursday morning . `` We know there 's no electricity tonight ... many of the families will be spending the night outdoors , in pitch black . I 'm very afraid of what might happen next , '' she said , referring to the possibility of aftershocks . Hundreds of houses have been damaged , Wayne Ulrich , the Red Cross disaster management coordinator in Indonesia , told CNN . `` We do not know the [ exact ] numbers . '' `` We have concerns that a hospital has been partially damaged , a market has caught on fire , the airport was closed down for inspection because of the fear if they landed any planes , '' it might cause problems , Ulrich said . Watch Ulrich discuss the rescue efforts » . Access to the affected areas was obstructed in parts , he added . It 's `` blocked by all kinds of problems : frightened people out in the streets , cars , and people trying to get out of the city . '' The earthquake was felt in nearby cities , such as Medan and Bengkulu , where people panicked and ran outside in search of higher ground , fearing a tsunami . But it was also felt as far away as Singapore and Malaysia . `` I did feel the tremor in office today somewhere between 5 - 6 p.m. , '' said Ratna Osman , who works in a single-story office building in Petaling Jaya , just outside Malaysia 's capital Kuala Lumpur . `` I asked [ a co-worker ] if there 's an earthquake somewhere -- either that or I was hallucinating . '' `` At first , I thought the chair I was sitting on had a screw loose or something , '' Osman said . The region is accustomed to earthquakes , and locals have been taught to identify safe places in case of a tsunami , according to Sean Granville-Ross , the Mercy Corps country director for Indonesia . `` We hope that preparation is now paying off , '' he said . But if many homes have been destroyed , people may be spending the night with no shelter , he said . Earlier this month , an earthquake in West Java killed 57 people . Several buildings were damaged , Metro TV reported , and people were seen running out of their homes and toward the hills . One employee of a private company in Jalan Ahmad Yani , told Antara news agency that `` everybody panicked with some shouting 'earthquake . ' '' TVOne pictures from the scene showed people milling around outside in the city . Phone lines were apparently down in many parts of Padang . Indonesia 's Tempo Interactive , a media outlet based in Jakarta , had trouble reaching its correspondent in the West Sumatra city , according to journalist Purwani Diyah Prabandari . `` I hope it 's just the cell phone connection , '' Prabandari told CNN . Indonesians trying to find out more about the quake flooded the Internet , including Twitter . Some expressed concern for relatives and friends in Padang . `` Dear God , please send down your angels to hug and protect my grandpa in Padang , '' said one Twitter post . The Web site for one of Indonesia 's main newspapers , The Jakarta Globe , crashed for a while , partly as a result of the heavy traffic from people trying to find out about the quake , the paper said in a Twitter post . The Pacific Tsunami Warning Center of the National Oceanic and Atmospheric Administration ( NOAA ) issued a tsunami watch for Indonesia , India , Thailand and Malaysia , but canceled it soon after . The temblor did generate a tsunami just under one foot high , the Pacific Tsunami Warning Center said . On Tuesday , a magnitude 8.0 quake-triggered tsunami killed at least 111 people in the Samoan islands and Tonga . Read latest news on the Samoa quake and tsunami . The tsunami waves swept across a wide swath of the Pacific Ocean , killing dozens and flattening or submerging villages . The dead included 22 in American Samoa , 82 in Samoa and seven in Tonga . Officials warned that the death toll could rise as rescue workers start to reach outlying villages and discover new casualties . The U.S. Geological Survey declined to say whether the two quakes were linked . `` The simple answer is we ca n't speculate on a connection , '' Carrieann Bedwell of the USGS told CNN . `` Both are in highly seismic areas . '' The epicenters of the two temblors are about 4,700 miles ( 7,600 km ) apart . CNN 's Tricia Escobedo and Andy Saputra contributed to this report .
NEW : Aid agencies kick into gear to help those in need . Second quake hits ; thousands feared trapped by collapsed buildings . Death toll could climb into thousands . Bridges down , phone lines in disrepair , says World Vision Indonesia .