Five days into the vast and sometimes violent street demonstrations over Friday's contested presidential election, Iran blamed the United States for "intolerable" interference in its domestic affairs.

President Barack Obama had specifically said he was avoiding being seen as meddling, saying it was "not productive, given the history of US-Iranian relations."

State television has portrayed the violence at rallies supporting defeated presidential candidate Mir Hossein Mousavi as the act of "hooligans." But as more video footage and news of peaceful daytime rallies and violent nighttime clashes break out through the restrictions placed upon the foreign media in Iran (most of it reaching the world anonymously through YouTube and Twitter), the contours of the power struggle have been coming clearer.

Three days after the Revolutionary Guards of the Sahrallah base took control of security of the capital from the police, according to sources in Tehran, a large pro-reformist rally packed a central Tehran avenue on Wednesday.

In another sign of the scale of unrest, five players and the captain of Iran's national soccer team wore wristbands of green – the color of Mousavi's movement – during the first half of their World Cup qualifying match in South Korea. The BBC reported they were told to take them off.

The protests are turning into an outlet for the myriad frustrations of Iranians, beyond rejecting the election result. State news services reported that the Revolutionary Guards had acted against "deviant news sites" backed by the US, Britain, and Canada that were encouraging unrest.

Grainy footage showed protesters carrying a wounded comrade as they raced from a clash. Another scene show a young man with a bleeding arm, and others rushing to bandage him.

The magnitude of the protests have prompted Iran's supreme leader Ayatollah Sayed Ali Khamenei – who will reportedly give the sermon himself at this week's Friday prayers – to call for calm.

• Material from the Associated Press was used in this report.