GAZIANTEP, Turkey — Turkey on Sunday expanded its investigations into contractors whose construction practices may have contributed to deadly building collapses in last week’s earthquake, and the United Nations’ top aid official said that humanitarian efforts had so far “failed” quake-stricken parts of Syria.
The 7.8-magnitude quake on Feb. 6 caused widespread destruction in 10 provinces in southern Turkey as well as in northern Syria, and killed more than 28,000 people, a toll that continues to rise. More than one million people have been rendered homeless in Turkey, and many others have been left without shelter in Syria.
Amid the destruction, the attention in Turkey has turned to what earthquake victims and building experts have called inferior construction that has left people’s homes particularly vulnerable to collapse.
The country’s vice president, Fuat Oktay, said on Sunday that the government had issued arrest warrants for 131 people suspected of wrongdoing that contributed to building collapses, and that 114 of them had been taken into custody.
On Saturday, the Turkish Justice Ministry ordered officials in the affected provinces to set up so-called earthquake crimes investigation units and to appoint prosecutors to bring criminal charges against contractors and others with connections to poorly constructed buildings that collapsed.
The quake destroyed thousands of buildings and damaged infrastructure on both sides of the border, but while aid for Turkey has flowed in from around world, almost none has reached northern Syria because of the complex political situation after more than 12 years of civil war.
The United Nations top aid official said on Sunday that aid efforts so far had “failed the people of northwest Syria,” while calling the earthquake the “worst event” in the region in a century.
“They rightly feel abandoned,” the official, Martin Griffiths, wrote on Twitter from the Turkey-Syria border. “Looking for international help that hasn’t arrived.”
He praised the response of the Turkish government, saying that victims of natural disasters were always disappointed by early relief efforts.
The Turkish government has mobilized an enormous aid effort, with tens of thousands of rescue workers working with volunteers from around the world to dig through the rubble of collapsed buildings for bodies and, occasionally, survivors. The government has also erected tent cities to house residents whose homes were destroyed and is distributing food, medicine and other items.
But largely because of political divisions on the ground in Syria, which is much poorer, aid efforts are severely lagging. The earthquake caused heavy damage regions in areas controlled by the government of President Bashar al-Assad and in enclaves controlled by anti-government rebels who are backed by Turkey.
Mr. al-Assad, long considered a pariah by much of the world for his troops’ brutality in the civil war, has sought to have all aid sent through his government. That aid, critics say, is then routed to his loyalists.
Only one border crossing into the rebel-held areas, Bab al-Hawa, has been authorized by the United Nations for the transit of aid shipments. There have been reports that the Syrian Red Crescent received permission to send 14 trucks through that crossing into Idlib Province, but it was unclear if that convoy had crossed. Even if it had, the cargo would be minuscule in comparison with the needs.
On Saturday, the authorities in Turkey began arresting contractors who had built structures that collapsed after the quake.
They included Mehmet Ertan Akay, the licensed builder of a collapsed complex in the city of Gaziantep, who was charged with involuntary manslaughter and violation of public construction law, a Turkish news agency reported. The Gaziantep prosecutor’s office said it had issued the detention order after inspecting evidence collected from the rubble of the complex he had built.
Mehmet Yasar Coskun, the contractor who built a 12-story building in Hatay Province with 250 apartments that was completely destroyed, was detained on Friday at an Istanbul airport while trying to board a flight to Montenegro. Dozens of people are thought to have died when the building collapsed. Mr. Coskun told prosecutors his building had been properly licensed and audited by local and state authorities, according to the state-run Anadolu News Agency. His lawyer suggested the main reason he had been detained was to assuage public anger.
Two builders of a collapsed 14-story building in Adana, who reportedly fled Turkey immediately after the quake, were detained in Northern Cyprus, according to the Turkish-controlled Northern Cyprus administration.
While most of the search effort in hard-hit Turkish cities on Sunday focused on finding and removing bodies, unlikely saves were made.
In Hatay Province, a team from Romania removed a 35-year-old man alive from a pile of rubble 149 hours after the quake, the CNN Turk television station reported.
“His health is good, he was talking,” one of the rescuers told the station. “He was saying: ‘Get me out of here quickly, I’ve got claustrophobia.’”
In another rescue broadcast live on HaberTurk television, a 6-year-old boy was pulled from the ruins of a building in the city of Adiyaman 151 hours after the quake.
Ben Hubbard and Safak Timur reported from Gaziantep, Turkey, and Gulsin Harman from Istanbul.