Prime Minister Justin Trudeau’s top advisers have had about a dozen high-level meetings with President-elect Donald Trump’s most trusted officials, CTV News has learned.

The two sides have met 10 or 12 times since the U.S. election, and as recently as Tuesday -- a five-hour meeting between Trudeau’s chief of staff, Katie Telford, his principal secretary Gerry Butts, White House chief strategist Steve Bannon and Trump’s son-in-law Jared Kushner.

The meetings have been mostly focused on trade, with the intention of convincing the incoming Trump administration that any tariffs on Canadian goods would hurt the U.S. economy.

CTV News was told that throughout these meetings, Trump's team became more receptive to Canada's case that the two economies remain integrated, that Canada is the biggest export market for 35 states, and so imposing taxes or tariffs at the border could hurt both economies.

The news comes as American Ambassador Bruce Heyman says he's leaving Ottawa in the next few weeks, following a New York Times report that Trump is denying diplomats' requests for extensions on their terms.

Heyman tweeted Friday morning, that he and his wife Vicki will be leaving Canada on or around Jan. 20, the day of Trump’s inauguration.

Heyman told CTV's Question Period last month, that outgoing U.S. President Barack Obama had asked all his political appointees to resign as of Trump's inauguration, following an example set by former president George W. Bush.

But Heyman suggested he was willing to remain until Trump found a replacement.

The New York Times report said several ambassadors, particularly those with school-aged children, had asked the Trump administration to remain in their posts for a few months, and some are now scrambling to obtain visas so they don't have to leave part-way through the school year.

The paper says it's a break with precedent, as most administrations allow a grace period.

The Heymans have grown children.

Heyman was an Obama fundraiser before he became his envoy to Canada.

Other major U.S. partners like Britain and Germany also have politically appointed ambassadors, while posts in other countries are filled by career diplomats who remain in their roles even when the administration changes.

Heyman became the U.S. ambassador to Canada in March, 2014, following a 33-year career at Goldman Sachs. He succeeded David Jacobson, Obama's first appointee as ambassador to Canada.

Vicki Heyman also tweeted about the departure, saying it's been "an honour & complete delight to represent the U.S. in Canada."

"We will miss all of you but promise to stay in touch!" she said.