SOS Mediterranee says Sunday that due to the recent refusal of Italy and Malta to let rescue vessels carrying migrants dock, ships might be unwilling to do rescues "due to the high risk of being stranded and denied a place of safety."
On Friday the group's ship Aquarius rescued 141 people in waters off Libya, AP reported.
SOS Mediterranee said "in a disturbing development, rescued people told our teams that they encountered five different ships that did not offer them assistance before they were rescued by Aquarius."
In June, Aquarius was forced to sail north for days with more than 600 migrants to Spain after Italy and Malta refused it docking permission.