A Russian researcher at Harvard University is being detained over failing to declare frog embryos while passing through customs, according to a filing by her attorney.

Kseniia Petrova's attorney said her previous arrest in Russia and social media activity "will almost certainly ensure a nice, hefty jail sentence for her" if she is deported back.

People need to understand who we’re fighting with here,” Olga Yilova, executive director of the nonprofit Olga’s List, which helps Ukrainian refugees, said on Sunday.