OTTAWA (Reuters) - Ontario, the most-populous province in Canada, complained on Monday the United States had blocked the export of more than 3 million face masks it bought to fight the coronavirus outbreak, while Ottawa said it was pressuring Washington to release the gear.

Slideshow ( 7 images )

The province bought two orders of almost 4 million medical masks from manufacturer 3M Co's MMM.N plant in South Dakota, and one batch of nearly 3 million was halted, Premier Doug Ford told reporters. Speaking to Global News, he called the incident "absolutely unacceptable."

Ford, a populist conservative, said that after the Ontario and Canadian governments complained, he had been assured 500,000 of the masks would soon be released.

U.S. President Donald Trump signed an order last week to stop personal protective equipment from being exported, and Ford said it was “absolutely critical” that Canada be exempted.

Ford said he would be calling U.S. Trade Representative Robert Lighthizer to press home the point.

Ontario, which has the second-highest number of coronavirus cases among the 10 provinces, would run out of personal protective equipment in a week, Ford added. About 14 million people live in Ontario, representing over a third of Canada’s population.

U.S. Secretary of State Mike Pompeo spoke to Canadian Foreign Minister Francois-Philippe Champagne on Monday and “reiterated the U.S. desire” to work with Canada to ensure the viability of international supply chains for medical supplies and personnel, a Pompeo spokeswoman said.

Canadian Deputy Prime Minister Chrystia Freeland told reporters that “we are working intensely with the United States to ensure that all the masks that have been bought can be exported to Canada.”

Allies of the United States have complained about what they call its “Wild West” tactics in outbidding or blocking shipments to buyers who have already signed deals for medical equipment.

Canada’s death toll from COVID-19, the respiratory disease caused by the novel coronavirus, had climbed to 340 by 5 p.m. (2100 GMT) on Monday, from 258 on Sunday, according to a tally of provincial announcements compiled by the Canadian Broadcasting Corp. The number of cases rose to 16,568 from 14,426.

In a sign of the economic challenge, officials said a total of 3.18 million people in Canada had filed unemployment claims since March 16, including for an emergency benefit that launched on Monday.

Industry groups and tenants said landlords should brace for rent strikes in May unless the government steps in with rental subsidies for occupants as the outbreak decimates wages.