A doctor at Gaza's largest hospital Al-Shifa told AFP that the facility's director and several other medical personnel were arrested by Israeli forces on Thursday.
Thee director, Mohammad Abu Salmiya, has been frequently quoted by international media about the conditions inside Al-Shifa, a major focus of the Israeli ground offensive following the militants' October 7 attacks.
The Israeli army, which raided the hospital last week, has alleged that Hamas fighters used a tunnel complex beneath the facility in Gaza City to stage attacks.
Hamas and hospital officials have repeatedly denied the claims.
"Doctor Mohammad Abu Salmiya was arrested along with several other senior doctors," said Khalid Abu Samra, a chief of department at the hospital.
An official in the Hamas-run health ministry specified to AFP that one other doctor and two nurses had been detained, as well as the hospital director.
In a statement, Hamas said it "strongly denounces" the arrest of Salmiya and his colleagues, calling on the International Committee of the Red Cross and other international organisations to work towards their "immediate release".
Instructions to evacuate the hospital were issued on Saturday, prompting the exodus of hundreds of patients and displaced towards the supposedly safer south of the Palestinian territory.
Salmiya told AFP last week that he had received the evacuation order from Israeli forces after having refused a previous one.
But the Israeli army said the evacuations were carried out at the "request" of Abu Salmiya.
The military released an audio recording presented as a conversation between Salmiya and a senior Israeli officer in which the two men blame each other for the evacuation.
Israeli officials claim Hamas operated a command centre in tunnels under the hospital for years -- an accusation the Islamist movement and medical personnel reject.
On Wednesday, Israeli soldiers escorted journalists to a tunnel shaft they said was part of a vast underground network used by Hamas.
Al-Shifa hospital has been the scene of an extended Israeli special forces operation as part of its war against Hamas in the Gaza Strip, where the Hamas-run government says more than 14,000 people have been killed, most of them women and children.
It came after Hamas militants poured across the border in an unprecedented attack on October 7. Israeli officials say about 1,200 people, mostly civilians, were killed and around 240 taken hostage.