Canadian Prime Minister Justin Trudeau says his government had no involvement in the arrest of a top executive from Chinese telecoms giant Huawei.
Meng Wanzhou was detained at Vancouver airport on Saturday on an extradition request from the US.
China has demanded her release, calling the arrest a human rights violation.
The charges remain unknown due to a court restriction but the US has been investigating Huawei over possible violation of Iran sanctions.
Huawei said it was “not aware of any wrongdoing by Ms Meng”.
She faces a bail hearing on Friday.
Who is Meng Wanzhou?
Ms Meng is the company’s chief financial officer and the founder’s daughter.
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.
The details of the charges against her remain unknown after she sought a publication ban, which was granted by the Canadian judge.
She was arrested while changing flights on Saturday. It was the same day that US President Donald Trump and Chinese President Xi Jinping met in Argentina for the G20 summit, where they agreed a 90-truce in their trade war.
What do we know about the arrest?
Speaking to reporters in Montreal, Mr 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.
US National Security Adviser John Bolton has also said he knew about the arrest in advance. He declined to say whether it was in relation to sanctions against Iran.
He added that the US has had “enormous concerns for years about the […] practice of Chinese firms to use stolen American intellectual property, to engage in forced technology transfers, and to be used as arms of the Chinese government’s objectives in terms of information technology in particular”.
“So not respecting this particular arrest, but Huawei is one company we’ve been concerned about,” he added.
US lawmakers have repeatedly accused the company of being a threat to US national security, arguing that its technology could be used for spying by the Chinese government.
The gloves are off
By Karishma Vaswani, BBC Asia Business Correspondent
It is hard to overstate the symbolism and significance of this event. Huawei is the crown jewel of Chinese tech and Ms Meng is effectively its princess.
Even though it’s still not clear what the charges against her are, this is not simply a case about the arrest of one woman, or just one company.
This arrest could materially damage the relationship between the US and China at possibly one of the most sensitive times between the two countries in their long and torrid history.
The gloves are off. Things have taken a dramatic turn for the worse.