Tens of thousands of people have taken to the streets of the Iranian capital in to mark the 1979 siege of the US embassy in Tehran. It is the latest in a series of massive anti-American rallies to celebrate the Islamist student action which dramatically changed relations between the states.The crowds also chanted support for President Mahmoud Ahmadinejad, who last week provoked international outrage by calling for Israel to wiped off the map. But despite his popular backing, he may face an uphill struggle to have Sadeq Mahsouli, his new choice for oil minister accepted by parliament. The job is the most prestigious and hotly contested in Iran’s cabinet. Much attention has been paid to the appointment after the president vowed to distribute the country’s oil wealth more fairly and remove the “mafias” who run the industry. Meanwhile, an investigation is underway after a small bomb exploded this morning outside the Tehran offices of BP and British Airways. No-one was injured. The same office was targeted by another device back in August.