An official said pipes at the entrance of unit 3 of the refinery caught fire. He did not say what caused the pipes to catch fire.
All eyes are on Iran in terms of the next moves it may make.
Britain separately announced its sanctions targeting senior Iranian decision makers enforcing Tehran's mandatory hijab law.
The UN said that this is "gender discrimination designed to bring the women of Iran into complete submission."
Tehran is expected to reach 39 C by mid-week.
Pro-regime media in Iran had to admit that the protesters had marched to Jerusalem and that Israel’s government is in Jerusalem, a tacit acknowledgement that Jerusalem is the capital of Israel.
The islands, Abu Musa and Greater and Lesser Tunb, are claimed by the UAE and Tehran, but have been held by Iran since 1971
Iran’s continued use of illegal actions also shows how it is willing to conduct destabilizing activities even as its diplomats work toward diplomatic goals with the Gulf states.
BEHIND THE LINES: Does Iran see an opportunity in the cracks in Israeli society?
Iranian naval "parade" involves some 2500 boats in support of the IRGC Navy