Rescue teams in Lebanon on Saturday said there was no longer any sign of life underneath the rubble of a building that collapsed following a massive explosion in Beirut on August 4, AFP reported. The blast ripped through the city, killing about 190 people and injuring more than 6,000. One month on, seven people are still listed as missing.

On Wednesday, a rescue dog detected movement under a destroyed building in Gemmayze area of Beirut, one of the worst affected by last month’s explosion. “These [signs of breathing and pulse] along with the temperature sensor means there is a possibility of life,” Eddy Bitar, a local non-governmental organisation worker, had told reporters at the scene. High-tech sensors confirmed an apparent heartbeat.

“Sadly, today we can say that technically we have no sign of life inside the building,” said Chilean rescue specialist Francesco Lermanda after three days of rescue work. He, however, added that work would continue to ensure there was no possibility of any victim being left inside.

About 50 rescue workers and volunteers, including a specialist team from Chile, had worked for three days to locate survivors, reported Reuters. Experts from Chile, France and the United States have been supporting Lebanon with the advanced search and rescue operations.

Earlier in the day, civil defence officer Qassem Khater had said that they would not give up. “We are not leaving the site until we’ve finished going through the rubble, even if a new building collapse threatens,” he had added.

Authorities said the explosion was caused by about 2,750 tonnes of ammonium nitrate that had been stacked in unsafe conditions in a port warehouse for years. Lermanda said efforts would now focus on clearing the rubble and finding remains.