July 22 (UPI) -- North Korea placed fourth at the 60th International Mathematical Olympiad in Britain, which concluded on Monday.
The country placed after the United States, China and South Korea in the world championship mathematics competition for high school students, South Korean news agency Yonhap reported.
The U.S. team tied for first place with China.
Pyongyang's team of teenage students earned a total of 187 points, an improvement from past performance. North Korea came in fifth from 2009 to 2013 at the annual tournament. It also placed fourth in 2015.
On Monday North Korea, an impoverished country under heavy sanctions for nuclear weapons development, outranked Thailand, which placed fifth.
North Korea also performed better than Russia, Vietnam, Singapore, Serbia, and Poland. Japan, the world's third-largest economy, was not among the top 10 teams at the Olympiad.
Britain, the host country, finished 21st in ranking.
South Korea's third-placing team included a team of six high school students, all from Seoul Science High School, an academy for "gifted students," according to an evaluation from South Korea's education ministry.
Cho Young-jun, a senior at the high school, solved all six problems and earned 42 points. He ranked first at the individual level, according to Yonhap, and was one of six contestants who received a perfect score. A total of 621 students from 112 countries competed at the tournament.
South Korean schools like Seoul Science High School are designated independent high schools with selective admissions, but the special status could be revoked for similar private high schools.
The JoongAng Daily reported Monday students from eight private schools in Seoul protested a pending decision to revoke the special status for their institutions.
The city of Seoul's education office had said the status could be revoked because the schools are too focused on college entrance exams.
The current administration of President Moon Jae-in could be planning to do away with independent high schools in order to create a more "equal environment," according to the JoongAng.