Tanzania has cancelled licences given to two ships to fly its flag after the vessels were seized carrying illicit drugs and explosives.
Vice-President Samia Suluhu Hassan said Thursday that the ships, named Kaluba and Andromeda, had been registered by the Zanzibar Marine Authority.
Kaluba was seized sailing near the Dominican Republic carrying 1.6 tonnes of cocaine on December 26, while Andromeda was seized by Greek authorities on January 6 carrying materials used to make explosives.
"We've revoked the licences and ordered the owners of the ships to lower the Tanzanian flag. We will also take action against those who registered the ships," said Ms Hassan at a press briefing at State House Dar es Salaam.
"When they were registered they signed declaration forms that the marine vessels would never be involved in illicit drug trade, ship weapons or be used for human trafficking. So, the fact that they have been seized for these very reasons, it means the owners have violated the laws," she added.
Ms Hassan said the directive to take action against those who registered the ships was given by President John Magufuli.
She added that she had held talks with the semi-autonomous Zanzibari government before the decision was reached.
The two governments will form a committee to review registration of ships that fly the Tanzanian flag.
Tanzania has in the past been on the spot over vessels it has flagged seized with illicit goods or from countries targeted by UN sanctions.
Last year, the government was forced to deregister 45 ships for breach of sanctions against North Korea.