A 16-year-old Ethiopian runner has been cruelly ridiculed online by social media users – including a Spanish athlete – who say she looks too old to be competing in an under-20 competition.

Girmawit Gebrzihair won the bronze medal in the 5,000m race at the World Under-20 Championships which are currently being held in Tampere, Finland.

But Gebrzihair's third place finish led to a backlash on social media from commenters who questioned her listed birth date of November 21, 2001.

However, none of the critics have provided any evidence to prove the provided birth date is false.

Girmawit Gebrzihair (pictured), a 16-year-old Ethiopian runner, has been ridiculed online by social media users who say she looks too old to be competing in an under-20 competition

Gebrzihair (circled) won the bronze medal in the 5,000m race at the World Under-20 Championships

Among those who mocked the athlete online was Oscar Husillos, a Spanish sprinter who specialises in the 200m and 400m.

The 24-year-old retweeted a picture of Gebrzihair, adding in Spanish: 'Her children and grandchildren are in the stands to see her run in the World U20 Championships.'

However, his tweet also sparked a backlash - with some slamming the athlete for his lack of respect and defended Gebrzihair.

'This comment is disrespectful. The IAAF should sanction you,' one person responded.

'You may have doubts about their age, but you could express them with more education,' another Twitter user said.

'You lack years of education and respect,' another said, adding that he should worry about his own performance instead of insulting someone else.

Among those who mocked the athlete online was Oscar Husillos, a Spanish sprinter who specialises in the 200m and 400m

Girmawit Gebrzihair (right) won the bronze medal in the 5,000m race at the World Under-20 Championships. Pictured left, Ejgayehu Taye and centre, Beatrice Chebet of Kenya

But others also made harsh jokes about Gebrzihair's appearance.

One person commented: '16? That woman has lived through the American Civil War, two world wars and saw Pele's Brazil lift the 1970 World Cup.'

Another said: 'That's Benjamin Button's cousin.'

And another added: 'Is there no other way of controlling these things apart from looking at a passport? It is hard to believe.'

Gebrzihair finished third behind her compatriot Ejgayehu Taye and Kenyan athlete Beatrice Chebet, who took gold in the 5,000m final.

MailOnline has contacted the International Association of Athletics Federations (IAAF) and the Ethiopian Athletics Federation for comment.