A Qatar World Cup stadium worker has died in a building site accident, the first work-related fatality to be announced by organisers of the 2022 football tournament that has been dogged by concerns about labour conditions.
Qatar has previously reported three deaths at stadium construction sites but said they were not "work-related".
The country is relying on its large workforce of Asian labourers to build stadiums and related infrastructure to cope with staging the tournament in the Middle East for the first time.
The Supreme Committee for Delivery and Legacy, which is tasked with building World Cup sites, did not name the worker who died on Saturday morning at Al Wakrah Stadium, or provide his nationality.
"It is with deep regret we announce a work-related fatality on one of our projects," the committee said on its website.
Qatari officials believe the worker was hit by a water truck.
"A full investigation is under way to determine the factors which contributed to the death of one of our workers," the committee said.
"The relevant authorities were immediately informed and the family of the deceased have been notified. We offer them all the necessary support they may need at such a difficult time."
Fifa said it "deeply regrets the loss of life" and is awaiting details from Qatari authorities on the circumstances that caused the accident.
"It is with great sadness that we send our sincere condolences to the victim's family and colleagues," the game's governing body said in a statement.
Al Wakrah Stadium, which is nine miles south of the capital Doha, is intended to resemble the sails on a traditional Qatari dhow boat and was designed by Zaha Hadid before the architect's death in March.
The 40,000-capacity venue is due to be completed by 2018 and host games up to the quarter-finals at the 2022 World Cup.
The country is expected to spend tens of billions before the tournament kicks off in November 2022, preparing eight new and renovated stadiums and related projects such as transport links and accommodation.