The International Committee of the Red Cross (ICRC) has suspended its field operations in the Gaza Strip after two of its staff were briefly abducted.
The workers - Italians Claudio Moroni, 36, and Gianmarco Onorato, 63 - were seized by gunmen near the southern town of Khan Younis.
They were later released, Palestinian security sources said.
It is the latest in a series of kidnappings of foreign workers in Gaza, which has seen increasing lawlessness.
ICRC spokesman Eyad Nasser told AFP news agency the committee had decided to halt its field work in Gaza.
"Our employees will stay in their homes and offices and only leave in emergencies," he said.
No group claimed responsibility for the abductions.
Last month a Spanish aid worker was kidnapped in Gaza and freed on the same day, while two foreign journalists were held there for nearly two weeks in August.