The Mombasa-based East African Seafarers' Assistance Program said the Ukrainian ship, sailing under a Belize flag, was seized on Thursday.
Ukrainian Defense Minister Yuri Yekhanurov, quoted by the news agency Interfax Ukraine, said its cargo included 33 T-72 tanks being sold to Kenya under a legal contract.
He told reporters in Kiev that the cargo included grenade launchers and ammunition.
"All this is being sold in full accordance with Ukrainian legislation," Yekhanurov was quoted as saying.
Kenyan government spokesman Alfred Mutua confirmed that the military equipment was destined for Kenya.
"The cargo in the ship includes military hardware such as tanks and an assortment of spare parts for use by different branches of the Kenyan military," he said in a statement.
What would you do?
Should Donald Westlake write this as a caper novel? I can just see Dortmunder trying to profitably dispose of 33 tanks and accessories. If it's transposed into science fiction, what large object(s) would the tanks turn into?