Meng Wanzhou, chief financial officer of Chinese telecoms giant Huawei, is facing fraud charges relating to alleged breaking of US sanctions on Iran, a Canadian court has heard.
Details of the charges were revealed when a publication ban was lifted by a judge in Vancouver.
Ms Meng, daughter of Huawei's founder, was arrested in the city on Saturday and faces extradition to the US.
The court is deciding whether or not to allow bail.
China has demanded Ms Meng's release, insisting she has not violated any laws.
What happened in court?
On Friday, US prosecutors told the Supreme Court of British Columbia that Ms Meng had used a Huawei subsidiary called Skycom to evade sanctions on Iran between 2009 and 2014.
They said she had publicly misrepresented Skycom as being a separate company.
Ms Meng faces up to 30 years in prison in the US if found guilty of the charges, the court heard.
Court reporters said she was not handcuffed for the hearing and was wearing a green sweatsuit.
The arrest has put further strain on US-China relations. The two countries have been locked in trade disputes, although a 90-day truce had been agreed on Saturday – before news of the arrest came to light on Wednesday.
Huawei is one of the largest telecommunications equipment and services providers in the world, recently passing Apple to become the second-biggest smartphone maker after Samsung.
Ms Meng's arrest was not revealed by Canadian authorities until Wednesday, the day of her first court appearance.
Details of the charges were also not revealed at the time after she was granted a publication ban by a Canadian judge.
On Thursday, Canadian Prime Minister Justin Trudeau said his government was told about the arrest a few days beforehand, but it did not play a role.
"I can assure everyone that we are a country [with] an independent judiciary," he said.