BEIRUT — Using cranes, bulldozers and their bare hands, Lebanese rescue workers searched the rubble Monday of a five-story residential building that collapsed after days of heavy rains, killing at least 20 people.

Most of the dead were foreign workers living in Lebanon. The owner of the building was arrested Monday, a day after the collapse.

"The ground shook like an earthquake, that's what we all thought," said Mazen Farhat, 46, who lives in the area and was passing by when the building collapsed. "I heard screams, and then the dust was everywhere, and I ran," he said as he stood among dozens of people watching the rescue efforts.

Building collapses in Lebanon are rare, and officials said the cause was not yet clear. It is possible that cracks in the old building were made worse by heavy rain or the effects of several nearby construction sites. Some residents reported hearing a small blast earlier this week, which turned out to be the snap of a pillar in the building.

Interior Minister Marwan Charbel said the building's owner, Michel Saadeh, was arrested and was being questioned.

Red Cross and civil defence workers in bright orange uniforms pulled out several bodies on stretchers Monday, rushing them away as relatives gasped and cried softly.

Rescue efforts were complicated Sunday by heavy rains and a thunderstorm.

Some 50 tenants lived in the building in Beirut's Fassouh district of Ashrafieh. It collapsed at around 6 p.m. Sunday as residents were returning home from work, increasing the number casualties, officials said.

The victims included eight Sudanese, two Filipinos, two Egyptians and two Jordanians, according to the security officials, who spoke on condition of anonymity in line with regulations.

Six Lebanese, including 15-year-old Anne Marie Abdel Karim, also died.

"I was asleep, I woke up and felt everything shaking and then something fell on me and I started screaming," said Antonella, Anne Marie's twin sister. She spoke to local reporters from her hospital bed, not knowing her sister had died. "Thank God it was just this, and nothing more," she said.

Among those presumed dead were also three brothers from the Farhat family who stayed on the ground floor after the building started to shake, trying to try and save their elderly father, Tanios Farhat, who was trapped inside. By afternoon Monday, the body of only one of the brothers Jihad Tanios, had been found.

Red Cross head of operations George Kattaneh confirmed the number of deaths and said 12 others were injured and were being treated in hospitals.

Several others were still missing, but officials said they did not expect to find any survivors. No survivors have been pulled out since late Sunday night.