The chief financial officer of China's tech giant Huawei is suing Canada over her arrest at the request of the US.

Meng Wanzhou was held in December at Vancouver airport on suspicion of fraud and breaching US sanctions on Iran.

On Friday Ms Meng filed a civil claim against Canada's government, border agency and police for "serious breaches" of her civil rights.

It came on the same day that Canada officially launched Meng Wanzhou's extradition process to the US.

China has attacked Ms Meng's arrest and the extradition process as a "political incident". She denies all the charges against her.

What does Ms Meng's lawsuit say?
Ms Meng's claim - filed in British Columbia's Supreme Court on Friday - seeks damages against the Royal Canadian Mounted Police (RCMP), Canadian Border Services Agency (CBSA) and the federal government for allegedly breaching her civil rights under Canada's Charter of Rights and Freedoms.

She says CBSA officers held, searched and questioned her at the airport under false pretences before she was arrested by the RCMP.

Her detention was "unlawful" and "arbitrary", the suit says, and officers "intentionally failed to advise her of the true reasons for her detention, her right to counsel, and her right to silence".

Where are we in the extradition process?
Ms Meng, 47, will next appear in court on Wednesday, when it will be confirmed that Canada has issued a legal writ over her extradition to the US. A date for an extradition hearing will be set.

But this is still the early stages. A judge must authorise her committal for extradition and the justice minister would then decide whether to surrender her to the US.

There will be chances for appeal and some cases have dragged on for years.

What is Huawei accused of?
The US alleges Huawei misled the US and a global bank about its relationship with two subsidiaries, Huawei Device USA and Skycom Tech, to conduct business with Iran.

Why Huawei matters in five charts
US President Donald Trump's administration has reinstated all sanctions on Iran removed under a 2015 nuclear deal and recently imposed even stricter measures, hitting oil exports, shipping and banks.

It also alleges Huawei stole technology from T Mobile used to test smartphone durability, as well as obstructing justice and committing wire fraud.

In all, the US has laid 23 charges against the company.

Some Western nations are reviewing business with the firm over spying concerns, although Huawei has always maintained it acts independently.

How has China reacted?

The arrest has seriously strained relations between China, and the US and Canada.

Beijing says it is an "abuse of the bilateral extradition treaty" between Canada and the US, and has expressed its "resolute opposition" and "strong dissatisfaction" with the proceedings.

China also says the accusations against Huawei, the world's second biggest smartphone maker by volume, are a "witch-hunt".

Two Canadian citizens are thought to have been detained in China in retaliation for the arrest.

China and the US are also engaged in tough trade negotiations to end a major tariff dispute.