There was no initial reports of damage, the agency said.
The quake jolted at 6:59 a.m. Jakarta time Tuesday (2359 GMT Monday) with epicenter at 103 km southwest Sumba Barat district of the province and a depth of 10 km under sea bed, official in charge of meteorology and geophysics agency Aziz Sugiarso said.
"For this quake, there were no signs of tsunami to occur so that we did not issue a warning for that," he told Xinhua by phone.
The intensity of the quake was strongly felt at 4 to 5 MMI (Modified Mercalli Intensity) in Tambolaka town of the province and 3 MMI in Waingapu town of the province, the official said.
The jolts were also felt in Sumbawa district and Bima town of nearby West Nusa Tenggara province, Sugiarso said.
"But we have not got any damages or casualty triggered by the quake," he said.
Nine minutes after the quake, an aftershock of 5.2-magnitude struck off the province, the official said.
Indonesia is prone to quake as it lies on a vulnerable quake-impacted zone so called "the Pacific Ring of Fire."
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