MANAGUA - Iran's foreign minister warned the West on Monday against "starting a conflict," saying it was not seeking confrontation after its military seized the British-flagged tanker Stena Impero in the Strait of Hormuz last week.

London described the seizure of the Stena Impero as "state piracy" and on Monday called for a European-led naval mission to ensure safe shipping through the Strait of Hormuz. 

Speaking in Nicaragua, Foreign Minister Mohammad Zarif said Iran had taken measures against the ship to implement international law, not in retaliation for the British capture of an Iranian tanker two weeks earlier in Gibraltar.

"Starting a conflict is easy, ending it would be impossible," Zarif told reporters after meeting his Nicaraguan counterpart.

"It's important for everybody to realize, it's important for Boris Johnson to understand, that Iran does not seek confrontation," he said, referring to the front-runner to become Britain's new prime minister.

"Iran wants to have normal relations based on mutual respect," he added.

Zarif said Iran acted when it observed that the UK ship did not follow regulations.

"The UK ship had turned down its signal for more time than it was allowed to (and) was passing through the wrong channel, endangering the safety and security of shipping and navigation in the Strait of Hormuz, for which we are responsible," Zarif said.

In contrast, he described the seizure of the Iranian ship as "piracy" and "violation of international law" by British and Gibraltar authorities.

(Reporting by Ismael Lopez, Writing by Daina Beth Solomon; Editing by Frank Jack Daniel and Jonathan Oatis) ((daina.solomon@thomsonreuters.com; +52 55 5282 7150;))