JAKARTA: A powerful earthquake rocked the Indonesian island of Sulawesi on Friday, triggering a 1.5-meter (5-foot) -tall tsunami that an official said swept away houses in at least two cities. Disaster agency spokesman Sutopo Purwo Nugroho said in a TV interview that the tsunami hit Palu, the capital of central Sulawesi province, and a smaller city, Donggala. He said houses were swept away and families were reported missing. Communications to the area were disrupted. "The cut to telecommunications and darkness are hampering efforts to obtain information," he said. "All national potential will be deployed, and tomorrow morning we will deploy Hercules and helicopters to provide assistance in tsunami-affected areas." Indonesian TV showed a smartphone video of a powerful wave hitting Palu with people screaming and running in fear. The water smashed into buildings and a large mosque that crumpled under the force. The region was rocked by a magnitude 7.5 earthquake Friday and numerous strong aftershocks including one of magnitude 6.7. The chief of the meteorology and geophysics agency, Dwikorita Karnawati, said the tsunami was up to 1.5 meters (5 feet) high. She said the tsunami warning triggered by the biggest quake, in place for about half an hour, was lifted after the tsunami was over. Palu"s airport halted operations for 24 hours due to earthquake damage, according to AirNav, which oversees airline traffic in Indonesia. Mirza Arisam, a resident of Kendari, the capital of neighboring Southeast Sulawesi, said his uncle and his family of five, including three children, were holidaying in Palu and unable to be contacted after the tsunami. Central Sulawsi was hit earlier Friday by a magnitude 6.1 earthquake that based on preliminary information killed one person, injured 10 and damaged dozens of houses. Television footage showed people running into the streets. Woman and children wailed hysterically in a video distributed by the disaster agency, which also released a photo showing a heavily damaged department store. "All the things in my house were swaying and the quake left a small crack on my wall," Donggala resident Mohammad Fikri said by telephone. Indonesia is prone to earthquakes because of its location on the "Ring of Fire," an arc of volcanoes and fault lines in the Pacific Basin. In December 2004, a massive magnitude 9.1 earthquake off Sumatra in western Indonesia triggered a tsunami that killed 230,000 people in a dozen countries.