(NEW YORK) —  Beirut inhabitants are holding their breath after signs of life were again detected in the rubble of a collapsed building of the Gemmayze neighborhood, where the search for a survivor one month after the Aug. 4 blast is still ongoing.

The rescuers were alerted on Thursday by their dog, Flash, who is trained to detect humans.

A machine detected a heartbeat around 17 bpm coming from a staircase between the building and a neighboring store, Lebanese Civil Defense told ABC News.

After a second day of search, the teams decided to leave the site on Friday evening and wait for the frequencies of cellphones to die down as people evacuated the area.

When they tested the machine again on Saturday morning, they detected a strong heartbeat and strong breathing.

However, search-and-rescue teams who were focusing their efforts on the staircase finished clearing the area by 2 p.m local time in the afternoon, without finding anything. They have now movedonto searching a collapsed roof area.

Riad Al Assad, the engineer overseeing the site for the Lebanese Civil Defense, said all areas where the machines picked up signs of life have now been cleared. The machines, the dog and the thermal cameras have always indicated [the] first roof, second roof [and] stairways.

“Third roof we had nothing there. Nevertheless, we’ll go to the extreme of our capabilities and remove the third [roof],” Al Assad said.

Parts of the city are still being cleared of rubble and glass after 2,700 tonnes of ammonium nitrate exploded at the port of Beirut, causing a shock wave that damaged swaths of the Lebanese capital and killed at least 180 people.

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