Turkish authorities have widened investigations in relation to buildings that collapsed in the catastrophic earthquakes earlier this month, which flattened swathes of the country’s southeastern region.

Investigations have been launched against around 612 people, and 184 suspects accused of responsibility for the toppled buildings have been taken into custody pending trial, Justice Minister Bekir Bozdağ said Saturday.

The magnitude 7.7 and 7.6 quakes struck on Feb. 6 in southeastern Türkiye, also severely hitting neighboring Syria, and destroying around 164,000 buildings, containing some 520,000 apartments, in what is described as the worst disaster in Türkiye’s modern history.

Overnight, the death toll from the earthquakes rose to 44,128 in Türkiye. That took the overall number of deaths in Türkiye and Syria to more than 50,000.

Those in custody as part of the investigation include construction contractors and building owners or managers, Bozdağ said in televised comments from a coordination center in the southeastern province of Diyarbakır, one of the 10 provinces hit by the disaster.

"The detection of evidence in the buildings continues as a basis for criminal investigations," the minister added.

Bozdağ last week said legal changes could be needed for crimes regarding construction permits and said the authorities should discuss harsher punishments and deterrents for violating zoning rules, which dictate where and how buildings can be more safely built.

Experts have said many toppled structures were built with inferior materials and methods and often did not comply with government standards.

Those formally arrested and remanded in custody include 79 construction contractors, 74 people who bear legal responsibility for buildings, 13 property owners and 18 people who had made alterations to buildings, he said.

The mayor of a town close to the epicenter of the earthquake was also detained, state broadcaster TRT Haber and other media reported.

Ökkeş Kavak, who heads the district of Nurdaği in Gaziantep province and is a member of the ruling Justice and Development Party (AK Party), is said to have failed to ensure construction inspections were carried out.

President Recep Tayyip Erdoğan has promised those responsible would be held accountable and pledged to rebuild homes and the southeastern disaster zone within a year.

Meanwhile, authorities have begun work to rebuild homes for the millions who need rehousing after the devastating tremors.

The government on Friday announced it started construction on 855 housing units in Gaziantep. It also issued new regulations under which companies and charities can build homes and workplaces to donate to the urbanization ministry for people in need.

Nearly 2 million people left homeless by the disaster are being housed in tents, container homes and other facilities in the region and in other parts of the country, Türkiye’s disaster management authority, AFAD, said.

More than 335,000 tents have been erected in the quake zone and container home settlements are being established at 130 locations, while nearly 530,000 people have been evacuated from affected areas, it added.

Many survivors have either left the southern region or have been settled in tents, container homes and other government-sponsored accommodations.

Erdoğan had said the government would cover the rent of those who leave quake-hit cities. "We will rebuild these buildings within one year and hand them back to citizens," he said.

The U.N. Development Program (UNDP) said it estimated that the destruction had left 1.5 million people homeless, with 500,000 new homes needed.

The initial plan is to build 200,000 apartments and 70,000 village houses at the cost of at least $15 billion. The bill to rebuild houses, transmission lines, and infrastructure could be around $25 billion, Wall Street bank JPMorgan said in a report.

Another report from the business association TÜRKONFED estimated damages to housing at $70.8 billion.

AFAD said that 9,470 aftershocks had hit the region affected by the quake.

"This will continue for a long time... we expect these aftershocks to last for at least two years," AFAD General Manager Orhan Tatar said in a media briefing in Ankara.

He said a 5.3 magnitude quake that on Saturday hit Bor, a town in Niğde province around 150 miles (about 245 kilometers) west of the Feb. 6 epicenter, was considered "independent" of earlier temblors.