Lawyers for Huawei executive Meng Wanzhou alleged in court documents released Wednesday that she was unlawfully detained and questioned by Canadian border agents in Vancouver last year.
Border agents detained her under the pretense of an immigration matter and never alerted her to a US warrant for her arrest, questioning her for hours before eventually handing her over to the Royal Canadian Mounted Police (RCMP), the lawyers said.
"From the outset of the applicant's detention," the RCMP and border agents were acting on behalf of "the FBI for the purpose of obtaining and preserving evidence," Meng's lawyers said.
"The question that remains is to what extent and how the FBI were involved in this scheme."
Surveillance video released by the court showed Meng moving through the Vancouver airport customs and immigration area, and being escorted and questioned by border agents.
The United States wants to put Meng -- who was detained on a US warrant in December 2018 during a stopover in Vancouver -- on trial for fraud for allegedly violating Iran sanctions and lying about it to US banks -- accusations her lawyers dispute.
Court documents showed that US-based Citigroup and French bank BNP Paribas were among four banks allegedly misled by Meng about Huawei's business dealings in Iran in breach of US sanctions.
HSBC Holdings and Standard Chartered had been previously named in the case.
Meng's detention provoked a diplomatic row between Canada and China. Her extradition hearing is scheduled for January.