Five Chinese sailors were abducted by pirates last week from a cargo ship in Nigerian waters, the Chinese foreign ministry said Monday.

"On July 2... a Singapore cargo ship was attacked by pirates in Nigerian waters and five Chinese sailors were kidnapped," the foreign ministry in Beijing said.

"The Chinese embassy in Nigeria has activated its emergency mechanism, requesting for Nigeria to take effective measures to search for the Chinese personnel who were taken."

Maritime security experts Dryad Global earlier said that the Singapore-owned Kota Budi cargo vessel was boarded by heavily armed men in the waters of Nigeria's neighbor Benin.

The Gulf of Guinea, which includes the Nigerian coast, is among the world's most dangerous waters as pirates regularly loot ships and kidnap sailors for ransom.

Dryad Global says 78 sailors have been kidnapped off the West African coast so far in 2020, a 26 percent increase on the figure from this time last year.

There was no official statements from the authorities in Nigeria or Benin on the incident.