TORONTO -- One day after a record number of new COVID-19 cases was reported worldwide, the head of the World Health Organization (WHO) warned that the pandemic is being worsened by political opposition.

WHO Director-General Tedros Adhanom Ghebreyesus said Monday that "the pandemic is still accelerating" and that "the lack of global solidarity and global leadership" represents a greater threat to the world than the virus itself.

"We cannot defeat this pandemic with a divided world," he told a virtual health forum organized by Dubai in the United Arab Emirates.

"The politicization of the pandemic has exacerbated it."

Speaking later in the day at a WHO press briefing, Tedros noted Sunday's record of 183,020 new COVID-19 cases being reported in a single day. That figure also represents the largest one-day increase on record.

"It seems that almost every day we reach a new and grim record," Tedros said.

"Some countries are continuing to see a rapid increase in cases, and some countries that have successfully stopped community transmission are seeing an upswing in cases as they reopen their societies and economies."

There have now been more than 8.8 million cases of COVID-19 confirmed around the world, as well as more than 465,000 deaths, Tedros said. As of noon EDT Monday, there had been more than 101,000 cases and more than 8,400 related deaths reported in Canada.

Tedros pushed governments to "double down" on testing suspected COVID-19 patients, isolating those who are sick and tracing and quarantining anyone who had been in contact with a known patient. He also urged individuals to maintain proper physical distancing, wash their hands with soap regularly and wear a mask when appropriate.

Nearly half of Sunday's record number of cases were recorded in Brazil and the U.S., the two countries that also have the highest COVID-19 death tolls in the world.

The increases are occurring even as some parts of the world forge ahead with reopening plans. This includes Canada and parts of Europe, where new case numbers have been decreasing, but also the U.S. and Pakistan, where they have not. In Australia, where the virus had seemed to be on the decline, new travel warnings were issued for Melbourne.

Rising case counts can reflect worsening COVID-19 situations, but testing increases and other factors can also play roles. However, Michael Ryan, the WHO's chief of emergencies, said Monday that the recent rise in new diagnoses is unlikely to be related to progress in testing.

With files from AFP and The Associated Press