Iran’s foreign minister, Mohammad Javad Zarif, said on Sunday that it was too early to talk about reopening the American Embassy in Tehran, Reuters reported.

The comments came as Britain restored its diplomatic mission in Tehran, four years after protesters ransacked the British ambassador’s residence.

Zarif was asked if Tehran would now countenance a restoration of the American diplomatic mission, and replied that the United States’ “illogical attitude” towards Iran meant the time was not ripe for a similar move with Washington.

“It seems that there needs to be a change in that kind of attitude and behavior on the part of the U.S. So the situation is different with the U.S.,” he said, according to Reuters.

The American embassy was sacked in the early days of the Islamic Revolution in 1979 by students who feared a repeat of a 1953 coup, when the CIA orchestrated the overthrow of Iran’s prime minister. The ensuing U.S. hostage crisis lasted 444 days and Washington and Tehran have yet to restore diplomatic ties.

Iran reopened its embassy in London on Sunday in a reciprocal move that followed a deal on Iran’s nuclear program reached last month with six major world powers, including Britain and the United States.

Britain’s move followed visits by several European officials to Iran since July 14, when the nuclear deal was struck.

Over the past few weeks, officials from Italy, France, Germany and Serbia have visited Iran. After the deal was signed, EU foreign affairs chief Federica Mogherini announced that she would visit Iran as well.

Hammond’s visit was the first by a British foreign secretary since 2003.