LONDON/TEHRAN -- Britain and Iran's worsening row over seized oil tankers showed no sign of letting up on Saturday as the countries' top diplomats emerged from a phone call as adversarial as ever.
British Foreign Secretary Jeremy Hunt wrote on Twitter that he "expressed extreme disappointment" to Iranian Foreign Minister Mohammad Javad Zarif for not moving to de-escalate the situation.
For his part, Zarif said, "The seizure of the British tanker was due to maritime violations and requested by the relevant port authorities," as reported by Iranian state media.
He was referring to the most recent development in the countries' feud, which occurred late Friday when Iranian officials detained two oil tankers in the busy Strait of Hormuz shipping lane.
Iran stopped the oil tanker Stena Impero and escorted it to the port of Bandar Abbas, where it will stay pending an investigation, Iranian media reported on Saturday, citing the port authority.
Iran also briefly held a second vessel, the Liberian-flagged but British-operated Mesdar, before releasing it later on Friday.
Zarif argued that Iranian authorities had acted legitimately and that the case must now be dealt with through legal channels, the IRNA news agency reported.
Port authority spokesman Morad Afifipur said the Stena Impero was seized after colliding with an Iranian fishing ship and ignoring the crew's distress calls.
The fishing boat then alerted maritime authorities, who stopped the tanker in accordance with maritime regulations and escorted it to Bandar Abbas, Afifipur said, according to Iran's Isna news agency.
Stena Bulk, the Sweden-based firm that operates the Stena Impero, said in a statement that the vessel was in "full compliance with all navigation and international regulations" when it was approached by "unidentified small crafts."