Mexico said Thursday its coronavirus death toll had risen above 100,000, becoming the world's fourth country to pass the grim milestone.

"Today in Mexico we have 100,000 people who have lost their lives due to Covid-19," deputy health minister Hugo Lopez-Gatell told a news conference.

The health ministry announced 576 more deaths in its daily update, taking the total to 100,104, behind only the United States, Brazil and India.

The overall number of infections registered now stands at 1,019,543 in the nation of more than 128 million, up 4,472 from the previous day.

While the number of daily infections has begun to rise again in recent weeks, the authorities say that deaths remain on a downtrend.

"There are infections, but fortunately... there are fewer deaths and that's the aim," President Andres Manuel Lopez Obrador said this week.

But Malaquias Lopez, an epidemiologist and former health ministry official, said it was unclear if the situation was improving.

"We're at a point where we don't see a clear phase of descent. We don't know where it's going," he told AFP.

The government says poor diets and health problems including obesity, hypertension and diabetes are partly to blame for the high death toll.

"These conditions increase the possibility of a patient dying, it's true, but in Mexico they're almost a death sentence," said Lopez, who thinks the authorities have used the risk factors to deflect criticism of their handling of the pandemic.

Half of Mexico's workforce is in the informal sector and if they become sick they cannot afford to self-isolate, he said.

The government says the high number of deaths reflects its large population.

When it comes to deaths per 100,000 inhabitants, Mexico is in 11th place worldwide, based on official data.

The authorities acknowledge that the real number of coronavirus deaths is higher than the official toll due to the low level of testing.

Luis Vargas, a doctor working at a coronavirus testing site in Mexico City, said that recently people seemed to have become more nervous because a relative or friend had caught the virus. 

He fears that many shoppers neglected to follow sanitary measures during the country's equivalent of the Black Friday sales this month.

"I think the number of cases is going to increase," he said.

Eighteen-year-old Aaron Romero, who was waiting to be tested and has symptoms of Covid-19, said his family had agreed not to get together at Christmas this year. 

"It's strange and difficult, but it's for the best," he said.