Five people broke into Iran’s embassy in Sweden on the outskirts of Stockholm on Tuesday afternoon before being evacuated, police in the Swedish capital said, AFP reported.

“Police were alerted to the Iranian embassy because there were people outside, and five people entered the embassy,” the statement said. One person was detained on suspicion of assault.

All people were evacuated, a TV4 spokeswoman said, adding that she could not say whether the gathering outside the embassy was permitted.

Relations between Sweden and Iran further soured in December after a Swedish appeals court upheld the life sentence of former Iranian prison officer Hamid Nouri for the 1988 mass executions.

Several Swedish nationals are being held in Iran, including Johan Floderus, a diplomat working for the European Union who went on trial in December on charges of conspiring with Israel.

Iran has already used foreign detainees as a ploy to free its citizens abroad, and Swedish media have also raised questions about the possibility of a prisoner exchange.