Libya's Islamist authorities say rescue workers have recovered five more bodies in the Mediterranean, raising the death toll from Tuesday's downing of a helicopter carrying two senior officials from the Islamist-backed Tripoli government from 14 to 19.

Wednesday's statement raising the toll followed another from Tripoli's rival, the internationally recognized government based in eastern Tobruk, denying responsibility for the attack. They had claimed responsibility a day earlier.

Tobruk's Wednesday statement said the spokesman behind the claim on Tuesday has been summoned for questioning.

Libya has fallen into chaos since the 2011 toppling and killing of longtime dictator Moammar Gadhafi, with two warring governments vying for control.

The helicopter was shot down near the coastal Almaya area west of Tripoli, which is rife with an assortment of rogue militias.