Ships have been urged to exercise extreme caution off West Africa after two suspicious approaches by pirates were reported in the last 24 hours.
Dryad Global said it had received reports of an unnamed merchant vessel spotting a skiff with four or five people on board on Thursday morning, 22 nautical miles (41 km) south of Cotonou, Benin.
The boat approached to within metres, the security consultancy added.
"Vessels should exercise extreme caution in the area and maintain watches 24/7 for any small craft acting suspiciously in the area, and report in to authorities any sightings," the company said.
There have been three piracy incidents so far in 2020 in the waters south of Cotonou. They involved two boardings and a kidnapping.
"This latest report is unusually close to the Cotonou anchorage areas with the majority of reporting in this area occurring at a distance of 50 to 80 nautical miles," Dryad Global said.
"Within 2019 there were two incidents recorded within the Cotonou anchorage."
More danger off Nigeria
On Wednesday, another cargoship reported being followed by an unidentified "craft" 110 nautical miles south-west of Nigeria's Agbami Terminal.
This followed an attack earlier in the day on Greek owner Niovis Shipping's 60,000-dwt Scarabe (built 2015),south-east of the terminal. This was averted by evasive moves.
It is possible that this is the same pirate craft. The distance between the earlier attack and this sighting also fits, Dryad said.
Scarabe had been approached by seven pirates on a speedboat.
Security consultancy Ambrey said the ultramax was outbound in ballast from Calabar in Nigeria at 11.1 knots, heading westbound.
Ambrey said in an update that it believed the vessel and crew are safe.
On Saturday, three people were kidnapped from the Equatorial Guinean-flagged, 1,000-gt ro-ro Elobey VI (built 1975) off Gabon.
Equatorial Guinea's ministry of defence said the pirates abandoned the vessel within 2.1 nautical miles of the Okwori terminal exclusion zone.
A day later, seven Ukrainian crew were kidnapped from the 957-teu boxship MSC Talia F (built 2015), 70 miles (1.6 km) to the north.
