DOHA, Qatar (AP) — Authorities in Qatar acknowledged on Thursday that three firefighters died last week during what officials say was a routine exercise unrelated to the upcoming World Cup.

Officials had declined to comment publicly on the deaths when they occurred. Local media reported that the three firefighters were Pakistani nationals who died when a crane collapsed.

Qatar has been under intense international scrutiny over its treatment of migrant workers as it prepares to host the world’s biggest sporting event later this month.

Col. Jabr Hammoud Jabr al-Nuaimi, a spokesman for Qatar’s Interior Ministry, told reporters that the three died during a “normal, standard training exercise” and that their families would receive compensation.

Qatar, like other Gulf Arab nations, relies heavily on migrant workers, who make up some 95% of its labor force. It has enacted a number of labor reforms in recent years that have been welcomed by the U.N. and rights groups. But those groups say exploitation is still widespread and more should be done to protect workers from wage theft and harsh conditions.

At the same press conference, Al-Nuaimi provided details about the security preparations for the World Cup, saying some 50,000 personnel would be deployed during the tournament. Qatar held five days of security exercises last week that included delegations from 15 countries, he said.