A suspected pirate boat pursued a tanker for 30 minutes off Ghana on Friday morning, before giving up the chase.
Piracy reporting body MDAT-GoG said the incident occurred 58 nautical miles south of Takoradi.
A 15-metre skiff with a red and white hull approached to within 50 metres.
There were six or seven people in the boat, but no weapons or boarding equipment were seen.
The crew and vessel have been reported safe.
Security consultancy Ambrey said it had tracked a Panama-flagged MR tanker, underway at 13.9 knots, perform evasive moves minutes before the time given by MDAT-GoG.
The tanker's AIS was displaying Lome, Togo, as its destination.
Security company Dryad Global said: "This latest incident has occurred at in an area absent of previous reporting.
"Within 2020 there has been one incident at the Takoradi anchorage north of this location. Within 2019 Takoradi had three reported incidents, however these were all reported within the anchorage area."
Maritime crime with the intent of boarding a commercial vessel would be a highly unusual incident within this location, it added.
