"In the hospital, under his management, there was extensive Hamas terrorist activity," it said in a statement.
Shifa Hospital, the biggest medical facility in the Palestinian Territories, has been at the centre of accusations of war crimes on both sides.
Hamas and doctors at the hospital have previously denied accusations that the complex was used for military purposes and dismissed the evidence presented by Israeli officials.
The army was still questioning him, army spokesman Lieutenant Colonel Richard Hecht told reporters on Thursday afternoon.
Palestinian Health Minister Mai Al-Kayla said the arrests showed that Israel was flouting international humanitarian law.
Persons:
Muhammad Abu Salamiyah, Abu Salamiyah, Richard Hecht, Hecht, Mai Al, Kayla, Israel, James Mackenzie, Howard Goller
Organizations:
Al, Al Shifa Hospital, Hamas, Shifa, Palestinian Health, United Nations, Cross
Locations:
JERUSALEM, Al Shifa, Gaza, Palestinian Territories, Israel