A shallow undersea quake measuring 6.8 on Richter scale rocked tourist resort of Bali province of Indonesia on Thursday, injuring at least 23 people, with one foreign tourist, and damaging buildings, but it was not potential for tsunami, officials said. The quake could be felt in nearby provinces of East Java and West Nusa Tenggara, official of the Meteorology and Geophysics agency named only Apprillianto told Xinhua. The quake struck at 10:16 a.m. Jakarta time (0316 GMT) with epicenter 143 km southwest Nusadua of Bali and the depth 10 km under sea bed, he said. The intensity of the quake was felt at 4 to 5 MMI (Modified Mercally Intensity) at coastal tourist resort of Kuta of Bali province and Mataram of West Nusa Tenggara province, 3 to 4 MMI in Madura island of East Java province, he said. The USGS put quake at 6.0 magnitude. In Kuta Bali, one of the hardest hit areas, roofs of school and office buildings collapsed that left at least 23 people injured, Disaster Management and Mitigation official in Bali province Wayan Suki, told Xinhua by phone. Nevertheless, in the others hard hit areas, Mataram of West Nusa Tenggara province there had been no immediate reports of damage or casualties, said Lili Widyanti the provincial disaster management and mitigation agency official. On Wednesday, nations along the Indian Ocean tested the first full-scale tsunami early warning system installed after the massive tsunami in Dec. 2004 that killed more than 230,000 people, Head of Indonesian Meteorology and Geophysics Agency Sri Woro B Harijono told Xinhua on Thursday. Indonesia, home of 129 active volcanoes, is earthquake-prone as it lies in a zone called \"the Pacific Ring of Fire,\" where two continental plates stretching from Japan to Western hemisphere meet, causing seismic and volcanic movements.