India has lifted its partial ban on the export of hydroxychloroquine, the anti-malarial drug that President Donald Trump has repeatedly touted as a coronavirus prevention and cure.

Only hours earlier Trump had warned of "retaliation" if India, one of the world's largest pharmaceuticals producers, did not reconsider the export ban.

India had imposed a partial ban on exports of the drug to protect domestic supplies.

There's still no conclusive evidence that hydroxychloroquine can prevent or treat the coronavirus.

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India has lifted its near-total ban on the export of hydroxychloroquine — a anti-malarial drug touted as a potential coronavirus prevention and cure — after being threatened by President Donald Trump.

Trump has repeatedly claimed that the drug prevent or cure the disease, and has described it as "one of the biggest game changers in the history of medicine."

The Food and Drugs Administration has not established the drug as a safe or effective coronavirus cure, and top public health official have refused to endorse the substance as a cure.

India had implemented a partial ban on foreign exports of the drug since March 25, and a total ban since Saturday, to protect domestic stocks.

But Trump has been placing pressure on Indian Prime Minister Narendra Modi to reconsider, and told a Monday briefing that he disagreed with the export ban, and threatened unspecified "retaliation" against the country if it didn't comply with his wishes.

"I spoke to him [Modi] Sunday morning, called him, and I said we'd appreciate your allowing our supply to come out," said Trump. "If he doesn't allow it to come out, that would be OK, but of course, there may be retaliation. Why wouldn't there be?"

In a statement released early Tuesday, the Indian government made no reference to Trump's threat, but announced it was partially lifting the ban in "appropriate quantities" given the "humanitarian aspects of the pandemic," reported local media.

India is one of the world's largest pharmaceuticals producers, and had earlier announced partial export ban on drugs including paracetamol, which it has also now partially lifted.

The country had implemented the export ban as the number of cases in the country continued to rise. As of Tuesday, the country has recorded more than 4,800 infections and 137 deaths, according to Worldometers — though the real number of infections is believed to be far higher.

Trump has for weeks pushed hydroxychloroquine as a potential coronavirus breakthrough drug, citing mainly anecdotal evidence.

Experts have warned of potential negative effects on patients from taking the drug — particularly those with underlying heart conditions. Clinical trials are underway in several countries to establish whether the drug is effective as a coronavirus treatment, but there is as yet no clear evidence that the drug works.

Nonetheless, the FDA has licensed discretionary use of the drug by medics to treat severely ill coronavirus patients, and the federal government has purchased and stockpiled 29 million pills of the drug.

"There is no evidence that these drugs will help people survive, and there is evidence that they can cause substantial harm, including blindness and heart failure," Diana Zuckerman, a drug safety expert at the National Center for Health Research, told Politico.

"These drugs can have dangerous interactions with other drugs, which older patients with other medical conditions may also be taking."