At least 25 people are feared to have drowned in a shipwreck off Libya after a dinghy, possibly carrying some 150 migrants, ran into trouble, two rescue organisations said Saturday.

"Rubber dinghy sunk north of Tripoli. At least 25 people died in the incident, exact numbers still unclear. Italian navy on the scene," the German charity Sea Watch said on Twitter.

The Italian coast guard told AFP 85 people had been rescued from the sinking vessel, and eight bodies recovered so far.