New coronavirus cases had their biggest daily increase ever as the pandemic worsens globally and has yet to peak in central America, the World Health Organization said on Monday, urging countries to press on with efforts to contains the virus.

"More than six months into the pandemic, this is not the time for any country to take its foot off the pedal," WHO Director General Tedros Adhanom Ghebreyesus told an online briefing.

More than 136,000 new cases were reported worldwide on Sunday, the most in a single day so far, he said. Nearly 75 percent of them were reported from 10 countries, mostly in the Americas and South Asia.