MONACO: Track and field athletes from Brazil, Ecuador, Peru and Portugal will be tested more often ahead of the Paris Olympics because of sub-standard anti-doping programs at home, the sport’s investigators said Monday.

Each country failed to heed warnings after the 2022 world championships held in Eugene, Oregon, to improve no-notice testing ahead of the 2023 edition, the Athletics Integrity Unit said, calling the targeted testing by nation “unprecedented.”

“All four failed to ensure that there was proportionate (out-of-competition) testing for their teams at the following world athletics championships in Budapest,” said the AIU, which is widely seen as the best among Olympic sports for investigating doping and corruption.

At the 2023 worlds, Ecuador and Peru each took home one silver medal and Brazil got one bronze. All were in race walking.

World Athletics has backed the AIU advice that non-elite athletes from the four countries can be eligible to compete in Paris only if they give at least three no-notice samples in training in the 10 months up to July 4. Track and field events in Paris start on Aug. 1.

“In this Olympic year, we trust this will be a reminder to all member federations that the AIU and World Athletics are extremely serious about ensuring a level playing field for athletes,” AIU chairman David Howman said.

Stricter testing will be demanded for athletes in endurance events, defined as “from 800 meters upward.” They also must give a blood sample for their biological passport and a test for EPO, the banned blood-boosting hormone.

The enhanced testing will be done on athletes outside the top 10 world ranking in their event. Elite athletes already are targeted by the AIU as likely medal winners at major championships.

The Monaco-based investigators said the targeted program will protect the Olympics “from athletes who emerge quickly through the rankings or produce surprise performances, or where the depth of talent means results are unpredictable.”

Two national track and field teams, the Czech Republic and New Zealand, also were warned about their anti-doping programs after the 2022 worlds and were praised on Monday as having “improved their testing dramatically.”