As many as 60 people are feared to have drowned on a vessel carrying migrants across the Mediterranean from Libya, the operators of a charity rescue group said on Thursday.

SOS Mediterranee said it rescued 25 people in a "very weak" condition in coordination with the Italian Coast Guard on Wednesday and that two unconscious people were flown to Sicily by helicopter.

"The survivors departed from Zawiya, Libya, seven days before they were rescued," SOS Mediterranee posted on the social media platform X.

"Their engine broke after three days, leaving their boat lost (and) adrift without water and food for days. Survivors report that at least 60 people perished on the way, including women and at least one child," it added.

There was no immediate comment from the Italian Coastguard.