A strong earthquake that scientists measured at 6.1 magnitude hit Port-au-Prince Wednesday, sending residents running into the streets eight days after the city was razed by a 7.0 quake.
The quake struck 59 kilometers (36 miles) west of the capital Port-au-Prince, according to the US Geological Survey (USGS).
It followed the much more powerful quake on January 12 that is thought to have killed 100,000 to 200,000 people.
Residents reported a low vibration followed by a brief but more powerful rumbling shake at 6:03 am (1103 GMT).
AFP reporters in the city said there was no immediate sign of damage or casualties but a crashing sound could be heard, suggesting an already damaged building may have collapsed.
In nearby Petionville, AFP staff said the quake was felt for around 10 seconds.
Residents ran into the streets in panic.
"It's the almighty. It's the almighty," one person could be seen saying close to Petionville's Hotel Kinam.
The USGS initially measured the quake at 6.0. It struck at a depth of 9.9 kilometers (6.2 miles).
In Paris, French seismologist Yann Klinger at the Institute of the Physics of the Globe (IPG) said the Wednesday's quake was one of a series of aftershocks.
These shocks were clustered in two areas, one closer to Port-au-Prince and the other -- the location of Wednesday's event -- further west, he said.
"It's not surprising to have an aftershock of this magnitude a week or so after the original earthquake," Klinger told AFP.
Under the logarithmic scale used to calculate so-called Moment magnitude, Wednesday's shock was around 30 times less powerful than the January 12 event, he said.
"Even so, it's a big earthquake, which means that any building that has been badly damaged may collapse."
Explore further: Modeling storm surge to better protect Texas