Mr Erekat, who tested positive earlier this month, was transferred from his home in the West Bank following a request by Palestinian officials.
Mr Erekat has been a key negotiator in peace talks with Israel for many years.
Witnesses told Reuters news agency that they saw Mr Erekat on a stretcher outside his home in Jericho, being placed in an Israeli ambulance.
His brother Saber Erekat told AFP news agency: "His situation is not good.".
Explainer: Israel, annexation and the West Bank.
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Covid-19: Top Palestinian official Saeb Erekat taken to Israeli hospital4
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