Los Angeles (CNN) Elon Musk said last month he had obtained more than 1,000 ventilators to help California hospitals treating patients infected with the coronavirus, an effort California Gov. Gavin Newsom hailed as "heroic."

Now, more than three weeks later, the governor's office says none of the promised ventilators have been received by hospitals.

At a March 23 news conference, Newsom said the devices, which can provide life-saving support to patients infected with the virus, had already arrived in Los Angeles and were on their way to hospitals in need.

"I told you a few days ago that he was likely to have 1,000 ventilators this week," Newsom said. "They've arrived in Los Angeles, and Elon Musk is already working with hospital association and others to get those ventilators out. It's a heroic effort."

Shortly after the dramatic announcement, Musk said in a tweet : "China had an oversupply, so we bought 1255 FDA-approved ResMed, Philips & Medtronic ventilators on Friday night & airshipped them to LA. If you want a free ventilator installed, please let us know!"

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