TEHRAN: Baton-wielding riot police clashed with opposition backers in Tehran who used a Shiite religious festival to stage new anti-government demonstrations on Saturday, an opposition website and witnesses said.

The reformist Jaras website also said security forces fired tear gas and warning shots to disperse protesters and also attacked a building housing an Iranian news agency, ISNA, where it said some demonstrators had sought shelter during the unrest.

At least two people were injured as police chased after demonstrators into the downtown building, a witness said.

In a sign the protests were spreading, another Tehran resident later said supporters of opposition leader Mir Hossein Mousavi, chanting “Death to the dictator,” clashed with police near a mosque in northern Tehran where reformist former President Mohammad Khatami had been due to speak.

“They are chasing people and beating them and trying to disperse them, but even ordinary Iranians are stopping their cars and shout ‘Ya Hossein, Mir Hossein’,” he said. Jaras said police also fired tear gas also during that incident.

The reformist Parlemannews website said dozens of hard-liners disrupted Khatami’s speech by attacking the venue, which is located in a compound where late revolutionary leader Ayatollah Khomeini used to live. “A few minutes ago over 50 hard-liners used chains, batons and pepper spray to attack a venue ... where Khatami was giving a speech,” it said.

The outbreak of new clashes underlines escalating tension in Iran, six months after a disputed election plunged the country into turmoil.

It was not possible to independently verify the Jaras reports as foreign media are banned from covering protests.

The official IRNA news agency said the “rioters” in central Tehran numbered only 150, adding they wanted to disrupt the mourning ceremonies but that police dispersed them.

Despite scores of arrests and security crackdowns, opposition protests have repeatedly flared since the June poll, which the opposition says was rigged to secure President Mahmoud Ahmad-inejad’s re-election.

Jaras said, “Well-equipped security forces are clashing violently with backers of the opposition in many parts of downtown Tehran” and added later “riot police are shooting into the air in Enqelab square to disperse demonstrators who chant anti-government slogans.”

IRNA accused foreign media of exaggerating the “unsuccessful gathering of rioters” and of trying to encourage people to take to the streets. The authorities had warned the pro-reform opposition against staging any new rallies on Saturday and Sunday.

Indicating possible further unrest, the opposition urged people to gather in the same Tehran area also on Sunday morning, according to mobile phone text messages.

Police chief Esmail Ahmadi-Moqadam said his force would firmly confront any unrest that caused “destruction and chaos” and arrest the leaders, ISNA reported.

Ahmadinejad said Iran’s foreign foes could not harm the Islamic state from inside the country, Fars news agency said. “They had planned a very complicated and wideranging scenario ... but they don’t know that a nation which is ready to sacrifice its life for its religious figures will destroy all their satanic attempts,” he said.

He also called European politicians “one more stupid than the other,” the semi-official news agency added.