April 21 (UPI) -- Iran on Tuesday demanded the United States release the Iranian-flagged container ship the U.S. military seized over the weekend, threatening to use "all its capacities" to defend itself as the cease-fire neared its end.

The U.S. military seized Touska on Sunday as it enforced a military blockade of Iranian ports and ships, raising already high tensions during a two-week cease-fire rapidly nearing its end that negotiators from both countries are to use to secure an end to the war.

U.S. warships intercepted Touska transiting the north Arabian Sea en route to Iran's Bandar Abbas port city for allegedly violating the blockade.

Iran responded with accusations of violating the cease-fire and drone strikes targeting U.S. military vessels, according to state-run media, though U.S. Central Command has yet to comment.

Iran's Foreign Ministry on Tuesday condemned the seizure of Touska as an "unlawful and savage act of the terrorist U.S. army," saying the "act of maritime banditry and terrorism" terrified the ship's passengers and crew, some of whose family members were onboard.