Tehran: A massive police deployment in Tehran prevented large-scale protests from erupting although Iranian opposition websites reported stray clashes and officials said the capital remained calm.
Fars news agency, meanwhile, said Faezeh Hashemi, daughter of former president Akbar Hashemi Rafsanjani, was briefly arrested after "leading anti-revolutionaries and rioters" in Tehran.
Witnesses said a heavy deployment of riot police and Basij militiamen in key Tehran squares including Haft-e Tir ensured that anti-government demonstrators were unable to stage significant protests.
Tehran was the epicentre of deadly anti-government protests in 2009 after President Mahmoud Ahmadinejad`s disputed re-election, and also saw clashes on Monday during a demonstration in which two people were killed.
On Sunday, supporters of opposition leaders Mir Hossein Mousavi and Mehdi Karroubi had called for fresh demonstrations and tried to stage them, their websites said. The two men refuse to acknowledge Ahmadinejad`s presidency.
Police maintained that Tehran had stayed calm.
"The situation in Tehran is normal and police have been deployed in Tehran... There were no special problems security-wise," said Ahmad Reza Radan, Iran`s deputy police chief, quoted by ISNA news agency.
In a separate report on Fars he was quoted as blaming the United States and Britain for "sporadic gatherings of monafeghins (hypocrites)”, a term officials use to refer to members of the outlawed People`s Mujahedeen of Iran.
Radan also said that police discovered a package of explosives with an electronic detonator and a small firearm with a silencer near a Tehran university.
Tehran traffic police chief Hossein Rahimi told state news agency IRNA that traffic was "heavy... but flowing" in the city.
Several opposition websites and witnesses reported scattered demonstrations in Tehran and some clashes between police and protesters.
"Police fired tear gas as a cat-and-mouse game (between police and demonstrators) began in Vali Asr Square" of Tehran, said the website Rahesabz.net, citing witnesses.
Crowds of demonstrators were also seen in other Tehran squares and some streets, shouting "Allahu Akbar" (God is Greatest), according to Karroubi`s Sahamnews.org website.
Fars reported Rafsanjani`s daughter was detained in the capital but later released.
"Faezeh Hashemi, who was arrested as she led a number of anti-revolutionaries and rioters while claiming to purchase clothes in Vali Asr Street, has been released," the report said.
Earlier, IRNA reported she was "identified and arrested by police in Vali Asr street while intending to make harsh comments and chant provocative slogans and create a disturbance”.
Rafsanjani himself has come under harsh criticism from conservatives who demand that he publicly condemn opposition leaders. The cleric and former two-time president reportedly supported Mousavi in the 2009 election.
Witnesses and opposition website Kaleme.com said men on motorbikes were riding around parts of Tehran "in a show of strength... to intimidate people and prevent them from holding large gatherings”.
According to Rahesabz.net, mobile phone networks in central Tehran were cut and Internet speed was "noticeably slow”.
Sahamnews.org said anti-government gatherings were staged in the central city of Isfahan and Shiraz, southern Iran, while Fars said the situation was calm in Iran`s second largest city, Mashhad in the northeast.
Foreign media have been banned from covering any opposition gatherings.
Sunday`s gatherings took place after a call on Thursday by the Council for Coordination of Green Movement Hope -- a group owing allegiance to opposition leaders -- to commemorate the killings of two people in Tehran last week.
Those protests, which saw demonstrators clash with security forces, were the first since February 2010 when the authorities marked the 31st anniversary of the Islamic revolution.
Nine security personnel were injured in Monday`s clashes, officials and websites said.
Anti-government protests erupted in Iran after a June 2009 presidential poll in which Mousavi and Karroubi, both candidates, charged that the incumbent, hardliner Ahmadinejad, was re-elected through massive fraud.