Iran’s Foreign Minister Mohammad Javad Zarif has congratulated Boris Johnson for his victory in the race to replace Theresa May as UK prime minister.

Ina tweet on July 23 Zarif attacked May’s government for “seizure of Iranian oil at behest of US” calling it a “piracy”.

Then he went on to congratulate Johnson, calling him “my former counterpart”.

Iran and the U.K. have been locked in a tense feud since early July when authorities in Gibraltar seized an Iranian supertanker with two million barrels of oil bound for Syria. They cited violation of EU sanctions on Syrian oil industry as reason for the seizure.

Iran threatened retaliation and last week it forced a British-flagged tanker to change course and detained it at an Iranian port.

Zarif’s tweet might be seen as an attempt to show goodwill toward the new British PM, as the crisis threatens to further isolate Iran.

Johnson is also close to U.S. President Donald Trump and he might tilt Britain’s Iran policy more toward the “maximum pressure” posture of the U.S.