NEW DELHI (AFP) -- India's capital New Delhi extended its lockdown Sunday as the country's coronavirus crisis grew, while the death toll from a fire that ravaged an Iraqi Covid-19 hospital rose to 82.

The creaking health facilities in poorer countries injected a note of caution a day after the number of vaccines administered globally surpassed the one billion mark.

Covid-19 has now killed more than three million people worldwide since emerging in China in December 2019.

Its latest focus is India, which has logged more than two million cases in the last seven days.

The country of 1.3 billion recorded 349,691 fresh infections and 2,767 deaths Sunday -- the highest since the start of the pandemic.

Worst hit was the capital, New Delhi, where the healthcare system is struggling to cope with the huge spike in cases, with reports of overwhelmed hospitals, severe oxygen and medicine shortages and patients' families pleading for help on social media.

"He was gasping for air, we removed his face mask and he was crying and saying 'save me, please save me'," Mohan Sharma, 17, said of his father, who died in a queue outside a hospital.

"But I could do nothing. I just watched him die."

A week-long lockdown in the megacity of 20 million, set to last until Monday, was extended by one week.

"The havoc of corona(virus) continues and there is no respite. Everyone is in favour of extending the lockdown," said Delhi Chief Minister Arvind Kejriwal.

On Sunday, Twitter confirmed it had withheld dozens of tweets critical of the unfolding crisis at the request of the Indian government.

The United States expressed concern over the surge in infections and said it would swiftly send help to India.

"Our hearts go out to the Indian people in the midst of the horrific COVID-19 outbreak," Secretary of State Antony Blinken tweeted late Saturday.

The fire at Baghdad's Ibn al-Khatib hospital started with an explosion caused by "a fault in the storage of oxygen cylinders", medical sources told AFP.

On Sunday, the Iraqi interior ministry said at least 82 people had died in the disaster, with 110 wounded.

Many of the victims were on respirators when the blaze started pre-dawn Sunday.

Flames spread quickly across multiple floors in the middle of the night, as dozens of relatives were at the bedsides of the 30 patients in the hospital's intensive care unit, a medical source said.

"The hospital had no fire protection system and false ceilings allowed the flames to spread to highly flammable products," Iraq's civil defence arm said.

Many "victims died because they had to be moved and were taken off ventilators, while the others were suffocated by the smoke," it added.

More than 200 patients in all were rescued, according to the health ministry.

With the pandemic still raging, governments around the world are placing their hopes on vaccines.

Worldwide, the number of vaccine doses administered has doubled in less than a month.

At least 1,002,938,540 vaccine doses have been administered in 207 countries and territories, according to an AFP tally.

Nevertheless, while most poor countries have also started to vaccinate -- mainly thanks to the Covax programme -- inoculation is still largely a privilege of high-income countries. Home to 16 percent of the world's population, they have administered 47 percent of vaccine doses.

By contrast, low-income countries account for just 0.2 percent of shots so far.

In the US, regulators ended the pause on Johnson & Johnson vaccines after determining the benefits outweighed the rare blood clotting risk.

In Europe, Belgium said Saturday it would authorise the J&J shot for all adults, having already received 36,000 doses and expecting a total of 1.4 million between April and June.

The European Union as a whole said it would have enough vaccines to immunise 70 percent of its adult population by the end of July.

But despite the optimism, the threat of the virus remains ever-present, with Germany implementing tougher lockdown rules, including night curfews and school closures, after the government passed a disputed new law designed to slow infections.

The controversial new rules -- passed this week amid huge protests in Berlin -- will apply in all regions with incidence rates of more than 100 new infections per 100,000 people over the last seven days.

Some normality was restored Sunday in Melbourne, where just over 78,000 spectators packed a stadium for an Australian Rules football match, in what is believed to be the biggest crowd at a sporting fixture since the pandemic began.