Switzerland's Massoel Shipping has confirmed that contact has now been made with those who are holding hostage 12 crew from its bulker Glarus.
It is understood that all the seafarers are together and all are well and unharmed, it added.
The 47,000-dwt ship (built 2001) was attacked off Bonny Island, Nigeria, on Saturday, and 12 of 19 crew kidnapped.
The vessel is now safely alongside at Port Harcourt with the remaining seven crew members on board.
