A group of South Korean students are suing the government because their college admission examination ended 90 seconds earlier than scheduled.

They are asking for 20 million won ($15,400; £12,000) each - the cost of a year's studying to retake the exam.

The error affected the rest of the students' exams, their lawyer says.

The country's infamous college admission test, known as Suneung, is an eight-hour marathon with back-to-back papers in multiple subjects.

The Suneung is one of the hardest exams in the world and stakes are very high.

It not only determines university placements and jobs but even future relationships. A number of measures to help students concentrate are taken during the annual event such as closing the country's airspace and delaying the opening of the stock market.

The results of this year's exam were released on 8 December.

The lawsuit, filed on Tuesday by at least 39 students, claims that the bell rang earlier at a test site in the capital Seoul during Korean - the first subject of the exam.

Some students protested immediately, but say the supervisors still took their papers away. The teachers recognised the mistake before the start of the next session, and gave the one and half minutes back during the lunch break but they could only mark blank columns left on their papers and were not allowed to change any existing answers.

The students said they were so upset that they could not focus on the rest of the exam, Yonhap news agency reports. Some reportedly gave up and returned home.

Their lawyer Kim Woo-suk told local media that education authorities had not apologised.

Public broadcaster KBS quoted officials who said the supervisor in charge of the specific test centre had misread the time.

This is not the first time students have sued over a bell rung too early. In April, a court in Seoul awarded 7 million won ($5,250; £4,200) to students who claimed they were disadvantaged at the 2021 Suneung exam because their bell rang about two minutes earlier.

And the price can be even higher in other countries. In 2012, a man in China was given a one-year suspended sentence for ringing the bell four minutes and 48 seconds early during the national college entrance exam at a school in Hunan province.