Some 244 deaths from the new coronavirus were recorded in China, out of this, 242 in Hubei province, on Wednesday - the deadliest day of the outbreak.
There was also a huge increase in the number of cases, with 14,840 people diagnosed with the virus, reports BBC.
Hubei has started using a broader definition to diagnose people - which accounts for most of the rise in cases.
Until Wednesday's increases, the number of people diagnosed in Hubei - where the outbreak emerged - was stabilising.
But the new cases and deaths in the province have pushed the national death toll above 1,350 - with almost 60,000 cases in total.
The province - which accounts for more than 80% of overall Chinese infections - now includes "clinically diagnosed cases" in the number of confirmed cases.
This means it includes those showing symptoms, and having a CT scan showing the infected lung - rather than relying only on the standard nucleic acid tests.
Of the 242 new deaths in Wuhan, 135 are such "clinically diagnosed" cases. That means, even without the new definition, the number of deaths in Hubei on Wednesday was 107 - a new high for the province.
The province's 14,840 new infections include 13,332 clinically diagnosed cases.
Overall, the province now has 48,206 confirmed infections.
Meanwhile, a cruise ship carrying more than 2,000 people has docked in Cambodia - after it was turned away by five countries over fears that some passengers might be infected with the virus.
The MS Westerdam arrived on Thursday morning after Japan, Taiwan, Guam, the Philippines and Thailand had all refused to accept the ship - despite having no sick patients on board.
"We've had so many near moments we thought we were going home only to be turned away," Angela Jones from the US told Reuters.
"This morning, just seeing land was such a breathtaking moment," she said. "I thought: Is this real?"
Cambodia's decision to welcome the ship was praised by the chief of the World Health Organization (WHO).
It was "an example of the international solidarity we have consistently been calling for", Director-General Tedros Ghebreyesus said.
The WHO also said it was "way too early" to predict the end of the epidemic.
"This outbreak could still go in any direction," he warned.
The WHO has been able to track down the source of transmission in all but eight of the 441 cases of the virus outside China, its head of emergencies Michael Ryan said.
He added: "I think it's way too early to try to predict the beginning, the middle or the end of this epidemic right now."
On Tuesday top Chinese epidemiologist Zhong Nanshan said the epidemic should peak in China this month before subsiding.
Four possible vaccines were being funded for pre-clinical development, WHO Chief Scientist Soumya Swaminathan told reporters.
"I think we will find a vaccine," she said. "It will take some time. A vaccine cannot be made overnight."