A trans swimmer and senior at the University of Pennsylvania, who previously spent three years competing as a man, smashed two US records while competing at a weekend contest, sparking fresh claims of unfairness.

On Sunday, Lia Thomas, 22, put in an astounding performance at the Zippy Invitational Event in Akron, Ohio, that saw her finish the 1,650 yard freestyle 38 seconds ahead of her teammate Anna Sofia Kalandaze.

Thomas's winning time was 15:59:71, with her UPenn teammate Anna Kalandaze coming second with a time of 16:37:44.

Thomas's win was a record for the Zippy Meet, and the pool where the event took place. But she also managed to smash two US women's swimming records during earlier races at the same event.

The first US record was broken on Friday, December 3, when Thomas won the 500-yard freestyle with a time of 4:34:06. She raced to victory 14 seconds ahead of Kalandaze - the swimmer she beat by 38 seconds on Sunday.

And then on Saturday, she won the 200 yard freestyle in 1:41:93 - seven seconds ahead of her nearest rival, giving her the fastest female US time ever for that race too.

It's the first season Thomas, who was formerly named Will, has competed in the swimming meets as a transgender woman. As Will, Thomas competed on the men's team for two full seasons.

This weekend she won three events and set three new school records including two new Ivy League records.