7.05am:

There has been an intriguing build-up to today's Quds ceremony (it's sometimes spelt 'Qods', I'm not sure which is correct). Here are the main developments:

• Quds, or Jerusalem, Day is celebrated in Iran as a day to denounce Israel. But the opposition is hoping to use it as an opportunity to vent their anger under the legal guise of an official rally, as Middle East analyst Meir Javedanfar explains.

• The defeated presidential candidates Mir Hossien Moussavi and Mehdi Karroubi, together with the reformist former president Mohammad Khatami, have pledged to attend the protests. Banners have appeared in Tehran with pictures of Mousavi bearing the slogan: "Quds Day, Green Day" referring to the colour that has become synonymous with the protest movement.

• Iran's police chief warned the opposition against using the ceremony as an anti-government demonstration.

• Hashemi Rafsanjani traditionally leads Friday prayers on Quds day, but he has been replaced by Ayatollah Seyyed Ahmad Khatami - a conservative cleric with strong ties to Ahmadinejad (not to be confused with former presidient Mohammad Kahatami).

If you need a catch-up on Iran, there's an informative discussion on what's been happening since the post-election unrest on Blogging Heads TV. Iran specialists Michael Rubin and Jamsheed Choksy cover Ahmadinejad's new cabinet, the economy, the future of the universities and the continuing power struggle between hardliners and the pragmatists within the regime. They agree that the radical question raised by the unrest is: "Why does Iran still need a supreme leader?"

There continues to be tough restrictions on journalists in Iran which means that reliable information is difficult to obtain, so if you are in Iran and have news, please email me at matthew.weaver@guardian.co.uk or post updates or interesting links in the comments section below.

7.10am:

Mahmoud Ahmadinejad again denied rigging the election. In his first interview with a western broadcaster he was asked twice, "Did you steal the election?"

He replied: "I don't know what you mean .... we should be courageous enough to accept the vote of the people."

He also described Neda Soltan's death as "suspicious".

7.20am:

Opposition rallies are planned in Tehran, Isfahan and Tabriz. Blogger homylafayette has published the planned routes of the marches.

7.30am:

A contact in Tehran says he plans to attend today's opposition rally, but he does not expect a mass demonstration like those in June. Asked on email how many he thought would attend, he said: "Not millions, but that's not important."

The man, an academic, added: "If there is any unrest that would be very embarrassing for the government on such a special day."

He said that while the willingness to demonstrate may have decreased, the anger has not, and the legitimacy of the regime has gone.

Asked what he thought of the leadership of the opposition he said: "I don't think very highly of politicians in such a system. We look forward to changes, not those who bring them about. When I voted for Mousavi I expected much less of him. I think he wasn't expecting it either. He turned into a revolutionary necessarily."

7.43am:

The are chants of "death to the dictator" in central Tehran, according to usually reliable reports on Twitter and ePersian radio, which is run by Iranian exiles in California. In between breaks for music it is broadcasting what sounds like mobile phone audio from protesters.

There are also reports that Karroubi has joined the protests.

8.05am:

Security forces have clashed with opposition protesters in Tehran, according to a flash on Reuters.

8.10am:

State-funded Press TV is showing live pictures of people gathering in Tehran for the official Quds day rally. Some are dressed in green, but its broadcaster claims those gathering are united in favour of Palestine.

Press TV also confirms that Ahmadinejad will be speaking at Friday prayers.

8.22am:

A picture claiming to show opposition supporters today in Karim Khan Street under a large green banner, has been posted by blogger onlymehdi.

8.40am:

State TV is broadcasting footage of Quds day rallies from previous years to hide the protests, according to blogger homylafayette. This is difficult to verify - there is a huge mismatch between the images claiming to show the official rally currently being broadcast, and the numerous reports of demonstrations posted on Twitter and blogs, and broadcast from Iranians outside Iran.

8.48am:

Ahmadinejad is giving a pre-sermon speech at Friday prayers at Tehran University. State-funded Press TV is broadcasting the speech live.

He begins with familiar anti-Israeli rhetoric. Speaking about the founding of Israel, he says "criminal Zionists usurped Palestinian land with the help of the British".

Meanwhile protesters have been chanting on the streets of Shriaz, according to this video, which is claimed to have been filmed today.

Another video from Shiraz shows opposition chanting anti-Russian slogans. They also shout 'Neither Gaza, nor Lebanon, my life for Iran', which suggests it was filmed today.

9.01am:

Thousand of protesters have shouted pro-opposition slogans today, according to the BBC.

9.08am:

An al-Jazeera's reporter in Tehran says he has witnessed opposition supporters chanting against the regime. He said they were out-numbered by those on the official rally and the security forces. He said the security forces were acting with restraint.

9.24am:

Ahmadinejad is still speaking about the "destruction of the Zionist regime". Once again he denied the Holocaust. "The pretext (Holocaust) for the creation of the Zionist regime (Israel) is false ... It is a lie based on an unprovable and mythical claim," he said according to Reuters.

9.29am:

There have been clashes between protesters and basij militia in Taleghani Square, in Tehran, according to a usually reliable source on Twitter.

9.33am:

Ahmadinejad has finished his speech. I didn't hear him make mention the protests or the disputed election.

9.38am:

CNN's ireport is showing an image of protester today splattered in blood with a gash on his head.

A new video purporting to show hundreds of protesters chanting in Isfahan today has been posted to YouTube.

9.49am:

Former president Mohammad Khatami has been involved in a scuffle. The reformist website Parleman News blames the attack on the son of the editor of the hardline newspaper Keyhan.

It is claimed that the windows of Khatami's car were reportedly smashed by hardline vigilantes when he turned up at today's rally. He was also said to have been jostled, with the result that some of his turban was knocked off, before being rescued by supporters.

10.02am:

A number of pictures showing green-clad opposition supporters have been posted to Twitpic.

10.16am:

A stream of videos all purportedly from today are being posted to YouTube by onlymehdi.

They include this one of protesters chanting support for Mousavi and former president Khatami.

10.39am:

A translation from the BBC's monitoring unit on that Parlemannews report confirms the attack on Khatami.

10.46am:

The Guardian's former Iran correspondent Robert Tait is monitoring events from Istanbul. He writes:



Ahmadinejad was giving a live interview on IRIB's Channel Two from the

scene of Quds Day. As he spoke, viewers could clearly hear the chants of "Ahmadi, Ahmadi, resign, resign" - this all over live TV. Apparently Ahmadinejad was aware of the chants and their effect on the interview. He is said to have become flustered and quickly wrapped up the interview.

11.11am:

Another video, just uploaded to YouTube by onlymehdi, purports to shows protesters chanting support for Mehdi Karroubi and "down the dictator".

11.17am:

Al Jazeera cites "reports" that Mousavi's car was attacked at the rally. But many claim this is incorrect. ePersian Radio says he was prevented from leaving home this morning.

This follows a familiar pattern. In the aftermath of the election there were numerous conflicting rumours about Mousavi. On most days there were reports on Twitter that he had been arrested. So far he has not been arrested.

11.39am:

"This is seriously big" says one of the comments on this new video which purportedly shows thousands of opposition supporters on Karim Khan Street, in Tehran today.

11.57am:

At least 10 protesters have been arrested, according to Reuters.

"Supporters of Ahmadinejad are beating supporters of Mousavi near the Vali-ye Asr street. At least two protesters were injured," it quoted a witness as saying.

12.02pm:

Al Jazeera's Alireza Ronaghi, reporting from Tehran, said the security forces were out in force, attempting to keep opposition demonstrators away from Tehran University where Ahmadinejad was speaking earlier.

"I didn't expect the protests to be as big," he said

Another video appears to confirm that thousands have been involved in the protests today. It also seems to show attempts to prevent filming taking place.

12.57pm:

NBC has released more of its interview with Ahmadinejad. In the latest segment, he defended the detention of three Americans, who have been held for more than seven weeks. They "trampled the law, and in accordance with the laws, they need to be punished," he said. The full interview will be broadcast on Sunday.

1.00pm:

There are widespread complaints from inside Iran of problems accessing the internet. Google Mail and Yahoo are both blocked in Iran, it is claimed.

1.05pm:

"If you arrest Mousavi and Karrubi, Iran will be hell," protesters were shouting today, the Tehran-based commentator Dr Mashallah Shams ol-Va'ezin, told Al Arabiya TV, according to the BBC's monitoring service.

He also described the demonstrations as "massive".

1.22pm:

The reformist website Parleman News has published images of former president Khatami appearing at the protests and the scuffle that followed.

1.31pm:

This is useful - a timeline of the protests since June 12 election, from Channel 4.

1.51pm:

A photo claiming to show Mousavi at today's protest has been published widely, including by blogger onlymehdi. As ever it's difficult to verify the date. Pictures claiming to show Rafsanjani and Karroubi have also been circulated. All the images are stamped with a Mehr News agency logo.

Update According to a 2:09pm posting by glcarlstrom in the comments section below the protesters behind Mousavi are carrying Quds day banners suggesting the photo was taken today. Thanks glcarlstrom.

2.33pm:

In his Friday prayer sermon the hardline cleric Ayatollah Khatami warned of the consequences of disunity, according to Press TV.

"No one doubts that unity is an absolute necessity for our Islamic country and that discord and lack of unity will only lead to destruction," he said.

He added: "The Islamic establishment is not opposed to the expression of different opinions and in the Islamic system difference of opinion is not a crime."

2.45pm:

David Miliband, the foreign secretary, is to issue a statement condemning Ahmadinejad's continual denial of the Holocaust.

(That's it for today. Thanks again for your comments and please keep them coming.)