Armed assailants laid siege on Sunday to a residence of Red Cross staff in the western Libyan city of Misrata, causing major damage to the building, the organisation said.
Seven staff were in the residence when the "unknown individuals" attacked the building with "various kinds of heavy weaponry" at dawn, said a statement from the International Committee of the Red Cross, adding that they were unharmed.
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"We are appalled by this latest act and by the deliberate targeting of our staff: they have put their lives at risk to serve the Libyan people both during and after the conflict," said Ishfaq Muhamed Khan, ICRC delegation head in Libya.
The Geneva-based organisation said that it has become extremely concerned about the "wave of attacks against humanitarian workers and the deterioration of the security situation in Libya."
"Given the circumstances, we are forced to announce, with considerable regret, that we will be suspending all our activities in Misrata and Benghazi and that our delegates in those cities will be temporarily relocated," said Khan.
"This most recent attack could have had very grave consequences for our colleagues," he added.