Canadian Prime Minister Justin Trudeau's Liberal Party appears to be ceding popularity to its Conservative rivals, according to polls published Saturday, with early elections only weeks away.

The Conservatives of Erin O'Toole, the main opposition party, took a slim lead as support for the Liberals has eroded in recent days, according to a tracking survey by Nanos Research conducted for the CTV network and the daily Globe and Mail.

The poll shows Conservatives favored by 33.3 percent of eligible voters, to 30.8 percent for Trudeau's Liberals, a difference just within the poll's margin of error but reflecting a steady swing away from the Liberals in recent days.

In mid-August, when Trudeau announced plans to hold an early election on September 20 -- less than two years after the last federal ballot -- his Liberals held a small lead.

But Trudeau's hopes of regaining a majority in the House of Commons appear a bit more tenuous today, Nik Nanos, founder of the eponymous polling firm, told CTV.

"It looks like the Conservatives are now gaining the upper hand and there is definitely negative pressure on the Liberals," he said.

The CBC public network's poll tracker also showed a narrow but growing shift in favor of the Conservatives, giving them a lead of 32.5 percent to 32.2 percent.

The Nanos poll put the left-leaning New Democratic Party in third position, supported by 21.7 percent of eligible voters. The CBC tracker had the New Democrats at 20.2 percent. 

Nanos showed O'Toole, who is still relatively unknown among the general public, with a rising approval rating, up 3.2 points to 27.2 percent since August 23. 

Approval for Trudeau slid by 2.8 percent, to 29.9 percent, over the same period.

Nanos noted that the decline in support for the Liberals came during a week when the election campaign was dominated by bleak news from Afghanistan, including the end of Canadian evacuation operations there.

Trudeau has also faced pushback over his response to the Covid-19 pandemic. 

On Friday, he had to cancel an election rally in the Toronto region because of angry anti-vaccination and anti-masking protests. 

The rolling Nanos poll is conducted by phone, with one-third of its 1,200 respondents contacted each night. It has a 2.8-point margin of error.