Fears of a second tsunami catastrophe in just over three months eased within hours, as officials in countries at risk reported their coasts clear of the type of earthquake-spawned waves that ravaged a dozen countries in Asia and Africa on Dec. 26.
Almost all the deaths reported after the 8.7-magnitude quake were on Indonesia's Nias island, a popular surfing spot off Sumatra island's west coast and close to the epicenter. Police were pulling children's' bodies out of the rubble of collapsed houses, and a fire was reportedly raging in one town.
"It is predicted and it's still a rough estimate that the numbers of dead may be between 1,000 and 2,000," Vice President Jusuf Kalla told the el-Shinta radio station, saying the estimate was based on an assessment of damage to buildings.
Other estimates varied. A district official in the town of Gunungsitoli said about 300 had died there, while Indonesia's information minister said between 100 and 200 had died.
Two people were also killed in Sri Lanka during a panicky evacuation from the coast in a Tamil rebel-held area, authorities said.
The U.S. Geological Survey said the quake struck about 19 miles under the seabed, some 155 miles south-southeast of Banda Aceh, the capital of Aceh province on Sumatra island. It was centered just 110 miles southeast of December's 9.0-magnitude temblor the world's most powerful in 40 years.
Monday's wallop, although very powerful, was but a fraction of the earlier quake. In explosive power, December's quake was equal to 100 million pounds of TNT; it caused the seabed to spring up as much as 60 feet.
Terrified of a disaster of equal proportions, sirens sounded throughout the region as authorities issued tsunami alerts for six countries after the quake struck at 11:06 p.m. as many people were sleeping.
Women clutching children ran into the darkened streets of Banda Aceh, crying and chanting "Allahu Akbar," or "God is Great." Others grabbed small bags of clothes and fled their tents and homes for higher ground.
Another man rushed instead to the local mosque, saying "Where can I go, you can't outrun a tsunami."
The quake lasted two minutes and briefly cut electricity in Banda Aceh. Thousands poured into the streets, where flickering campfires and motorbike and car headlights provided the only lighting.
People grabbed small bags of clothes as they fled their tents and homes. Many were crying and jumping into cars and onto motorbikes and pedicabs to head for higher ground. Two women wearing prayer shawls and sarongs grabbed a fence to steady themselves.
"People are still traumatized, still scared, they are running for higher ground," said Feri, a 24-year-old aid volunteer who goes by one name.
In Sri Lanka, warning sirens blared along the island nation's east coast and President Chandrika Kumaratunga urged people to evacuate immediately to higher ground.
"It was like reliving the same horror of three months ago," said Fatheena Faleel, who fled her home with her three children after seeing the warning on television.
In Malaysia, residents fled their shaking apartments and hotels.
"I was getting ready for bed, and suddenly, the room started shaking," said Jessie Chong, a resident of the largest city, Kuala Lumpur. "I thought I was hallucinating at first, but then I heard my neighbors screaming and running out."
The quake was felt as far away as Singapore and the Thai capital, Bangkok, more than 435 miles from the epicenter.
Nias island was badly hit on Dec. 26, when at least 340 residents were killed and 10,000 were left homeless.
The devastation there from Monday's quake appeared to be far worse.
Indonesian President Susilo Bambang Yudhoyono said early Tuesday he would fly to the stricken island to assess the damage for himself.
In the town of Gunungsitoli, about 70 percent of buildings collapsed in the market district, officials said.
"Hundreds of buildings have been damaged or have collapsed," said Agus Mendrofa, the island's deputy district head. He told el-Shinta radio station that at least 296 people had died in Gunungsitoli.
The MISNA missionary news agency in Rome, Italy, reported that a huge fire was raging early Tuesday in Gunungsitoli.
"From the window I see very high flames," MISNA quoted Father Raymond Laia as saying by telephone about two miles from the town. "The town is completely destroyed. I repeat, the town is completely destroyed."
But an overflight of the town at low altitude later revealed that although many houses had sustained damage, the overall level of destruction appeared to be lower than initial reports indicated.
Another police officer, who identified himself as Nainggolan, said rescuers were trying to pull people out of the rubble, and that many were still panicking because of several aftershocks.
"We are busy now trying to pull people or bodies of children from the collapsed building," said Nainggolan, who like many Indonesians uses only one name. "It is very hard also because there is no power."
"The situation here is really messy," he said. "Aftershocks keep hitting every half hour making thousands of people flee their homes and afraid to go home."
U.S. State Department deputy spokesman Adam Ereli said U.S. diplomatic missions in Asia and Africa went into "battle mode" to respond quickly to any contingency. Authorities worldwide had been slow to recognize the magnitude of the Dec. 26 disaster, which killed at least 175,000 people in 12 Indian Ocean nations and left another 106,000 missing.
Preliminary indications were that energy from Monday's quake might be directed toward the southwest, said Frank Gonzalez, an oceanographer with the National Oceanographic and Atmospheric Administration in Seattle.
The only tsunami reported was a small one 10 inches at the Cocos Islands, 1,400 miles west of Australia. Hours later, Australian meterologists reported a tsunami-caused wave of 10 to 20 inches hitting to the north and south of the Western Australia state capital Perth. No damage was reported in either area.
Officials said after the December disaster that a tsunami early warning system could have saved many lives. Such a system exists in the Pacific but has not been established in the Indian Ocean. Japan and the United States had planned to start providing tsunami warnings to countries around the Indian Ocean this month as a stopgap measure until the region establishes its own alert system.
But for residents of ravaged Banda Aceh, no warning system was needed after they felt the quake and headed for higher ground.
At the city's biggest refugee camp, a voice on loudspeaker later announced that there was no tsunami. This time, the voice said, people could return to their tents.