(CNN) -- A tsunami advisory announced shortly after a 7.0-magnitude earthquake struck Japan's Ryukyu Islands early Saturday has been canceled, Japan's Meteorological Agency reported. 
 
 There was no tsunami damage "though there may be slight sea level changes from now on," it said, referring to the areas affected by the advisory -- the Okinawa Islands, the Amami Islands and the Tokara Islands. 
 
 The quake was centered 10 kilometers (6.2 miles) deep and struck at 5:31 a.m. (3:31 p.m. ET Friday) about 85 kilometers (53 miles) from Okinawa. 
 
 The quake was felt on Okinawa, with shaking that lasted about 15 seconds, said Lt. Col. Daniel King of the U.S. Pacific Command. He told CNN that commanders in Japan and Hawaii were trying to get damage and casualty reports from U.S. military stations on Okinawa, but had heard nothing in the immediate aftermath. 
 
 About 20,000 U.S. troops -- mostly Marines, along with Navy and Air Force personnel -- are stationed on eight bases on Okinawa, he said. 
 
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 iReporter Kristina Donaldson, who lives in central Okinawa, said the quake "seemed to last longer than other ones we have experienced here." 
 
 "We felt the quake pretty good this morning," she said, but life there was largely unaffected. 
 
 "I just walked down to the coastline and the kids are walking to school as they always do. No sirens, or any destruction from where we are." 
 
 Okinawa resident Eric Shepherd said his grandmother-in-law described it as the strongest quake she had felt in her 90 years on the island. 
 
 "It felt like some really bad airplane turbulence," Shepherd said, adding that one of his two children slept through what seemed like a minute-long "rumble." 
 
 "I had no problem walking to the kids' room to check on them" during the quake, he said. 
 
 CNN's Mike Mount contributed to this report. ||||| TOKYO | 
 
 TOKYO (Reuters) - A strong earthquake hit Japan's southern island of Okinawa early on Saturday and Japan's weather agency issued a tsunami warning for up to 2 meters, but this was later lifted and there were no reports of major damage. 
 
 The U.S. Geological Survey said the 7.3 magnitude quake struck at 5:31 a.m. on Saturday (2031 GMT on Friday) 52 miles east of the island's capital of Naha, a city of about 320,000 about 1,600 km (1,000 miles) south of Tokyo. 
 
 The Japan Meteorological Agency, which put the magnitude at 6.9, warned residents near the coast to evacuate to high ground, but the tsunami warning was later lifted. 
 
 Okinawa prefectural police official Noritomi Kikuzato told Reuters there were no reports of injuries or major damage. 
 
 "First there was a strong vertical shake, then sideways. The strong quake lasted for about 10 seconds," said Naha city official Seiboku Sueyoshi. 
 
 An official at oil refiner Nansei Sekiyu KK said operations at its 100,000 barrels per day Nishihara refinery on the island were continuing normally after the quake and that there had been no reports of major damage to the facilities. 
 
 Public broadcaster NHK said local fire departments so far had no reports of injuries or damage to buildings. 
 
 Earthquakes are common in Japan, one of the world's most seismically active areas. The country accounts for about 20 percent of the world's earthquakes of magnitude 6 or greater. 
 
 In October 2004, an earthquake with a magnitude of 6.8 struck the Niigata region in northern Japan, killing 65 people and injuring more than 3,000. 
 
 That was the deadliest quake since a magnitude 7.3 tremor hit the city of Kobe in 1995, killing more than 6,400. 
 
 (Reporting by Yoko Kubota, Chris Gallagher, Edwina Gibbs and Osamu Tsukimori; Writing by Linda Sieg; Editing by Charles Dick)
– A tsunami warning has been lifted and residents of Okinawa are breathing a sigh of relief after an earthquake rattled the southern Japanese island early Saturday morning. " First there was a strong vertical shake, then sideways," an official of the city of Naha tells Reuters. "The strong quake lasted for about 10 seconds ." There were no immediate reports of damage or casualties on the eight American military bases in the area, CNN reports.