Witnesses in Iran's capital say security forces are patroling the streets, including the sites of Saturday's deadly protests against President Mahmoud Ahmadinejad's disputed election victory.
There has been no word on whether demonstrators were gathering Sunday, but Tehran remains tense following a week of sometimes violent protests.
State-run television says 13 people were killed Saturday in clashes with police.
Thousands had rallied in Tehran, despite a warning by the country's supreme leader, Ayatollah Ali Khamenei, to stop demonstrating about the disputed June 12th elections.
Witnesses said riot police used tear gas, batons and water cannons to disperse the crowds. Some demonstrators chanted "death to the dictator."
Iranian media say the daughter of one of Iran's most powerful figures, former president Hashemi Rafsanjani, and four family members were arrested during the protests.
State media also quote Parliament Speaker Ali Larijani as saying everyone should respect the opinions of those who believe the nation's election results are not accurate. He said the Guardian Council (-- which supervises Iran's elections --) should thoroughly investigate those claims.