People in Bangkok gathered to pray for victims and those still missing after a high-rise building under construction collapsed in a massive earthquake on March 28.



The authorities said on Thursday that 23 people have been confirmed dead, and more than 70 are still unaccounted for.



Buddhist monks, family members, and Bangkok Governor Chadchart Sittipunt took part in a religious ceremony on Thursday. It was held at the site where the State Audit Office building came crashing down.



The attendants prayed for the missing construction workers to be found, and for the search operations to proceed safely.



A woman searching for her son said she prayed for his spirit to come back home, even though his body had not been found. She said she hoped to see him.



The government is investigating what caused the tower to totally collapse. Officials at Thailand's industry ministry said on Thursday they had found some steel samples from the rubble that failed to meet quality standards.



But they added it was not clear how much substandard materials contributed to the accident.