Iran's Foreign Minister Mohammad Javad Zarif on Tuesday congratulated incoming British Prime Minister Boris Johnson, saying in a tweet that Tehran does not seek confrontation with London.

"I congratulate my former counterpart, @BorisJohnson on becoming UK PM," Zarif said on Twitter. "Iran does not seek confrontation. But we have 1500 miles of Persian Gulf coastline. These are our waters & we will protect them."

"The May govt's seizure of Iranian oil (tanker) at behest of US is piracy, pure & simple," Zarif added.