Tsunami alert for Indian Ocean nations after 8.6-magnitude quake strikes off Indonesia Updated at 8:10 a.m. (CBS/AP) BANDA ACEH, Indonesia - A massive earthquake off Indonesia's western coast triggered tsunami fears across the Indian Ocean on Wednesday, sending residents in coastal cities fleeing to high ground in cars and on the backs of motorcycles. A strong aftershock nearly three hours later sparked a new wave of panic. Indonesia's government responded by issuing a fresh tsunami warning. Some residents were crying in Aceh, where memories of a 2004 tsunami that killed 170,000 people in the province alone, are still raw. In Banda Aceh, Aceh's main provincial city, Indonesia's disaster mitigation agency said sirens and Koran recitals were heard from mosques around the city. The U.S. Geological Survey said the first 8.6-magnitude quake was centered 20 miles beneath the ocean floor around 269 miles from Aceh province. That prompted the Pacific Tsunami Warning Center in Hawaii to issue a tsunami watch for Indonesia, India, Sri Lanka, Australia, Burma, also known as Myanmar, Thailand, the Maldives and other Indian Ocean islands, Malaysia, Pakistan, Somalia, Oman, Iran, Bangladesh, Kenya, South Africa and Singapore. In India, CBS News' Sanjay Jha reports that the government had asked local states to advise fishermen not to venture out to sea because of the tsunami threat but then revised its warning ruling out the possibility of a tsunami hitting the country. A wave measuring less than 30 inches high rolled to Indonesia's coast. There were no other signs of serious damage. The head of Aceh's police said the province was safe from a tsunami threat not long after the Meteorology, Climatology and Geophysics Body announced a tsunami would hit the region, CBS News reports. People along the western coast of Sumatra island and the Mentawai islands were told to stay clear of coasts. The Pacific Tsunami Warning Centers watch remained in effect. The initial quake was a strike-slip, not a thrust quake, according to experts. They were still analyzing the aftershock. "When I first saw this was an 8.7 near Sumatra, I was fearing the worst," Roger Musson, seismologist at the British geological survey who has studied Sumatra's fault lines, noting one of the initial reported magnitudes for the quake. The first tremor was felt in Malaysia, where it caused high-rise buildings to shake for about a minute, and in Singapore, Thailand, Bangladesh and India. It caused chaos in the streets of Aceh.