Gaza’s Civil Defence Agency says it lost contact with six of its members who went on a rescue mission in the southern city of Rafah, Al Jazeera reports.

Its first responders and others from the Palestine Red Crescent Society went to Rafah on Sunday after receiving calls that Israeli troops entered the area of al-Hashaashin, in western Rafah, and there were casualties.

Since then, there’s been no word from the rescuers, the agency said in a statement.