The apparent kidnapping is the latest in the Gulf of Guinea, an area off the Atlantic coast of Africa whose waters -- rich in hydrocarbons and fisheries -- stretch across a slew of jurisdictions, including those of countries with limited naval and coast guard capacities.

Just before 6:00 p.m. on Thursday, seven armed individuals boarded the Mengxin I vessel in Ghanaian waters and fired warning shots, the Ghanaian military said in a statement.

The assailants rounded up members of the crew and sent others into hiding.

By the time the attackers departed three hours later, the captain, chief mate and chief engineer -- all Chinese nationals -- were missing, according to the statement, dated Saturday.

They are "suspected of being kidnapped by the attackers," it said.

Ghanaian authorities are sharing information with other members of west African regional bloc ECOWAS, it added.

In 2022, a UN Security Council resolution co-sponsored by Ghana and Norway was issued to condemn the spike of piracy in the Gulf of Guinea.

A study published in 2021 by the Stable Seas research institute found that pirate groups, mostly in the Niger Delta, can earn around $5 million per year through theft and hostage-taking.

That same year, a Danish naval patrol killed four pirates in an exchange of fire off the coast of Nigeria.