( CNN ) -- Protesters gathered in Iran on Friday for a demonstration to observe an annual holiday that marks the country 's solidarity with Palestinians and calls for the end of Israel occupation . One notable absence was Iranian opposition leader Mehdi Karrubi , whose security force feared for his safety and advised him to stay away , his son said . About 50 people surrounded Karrubi 's home Friday morning -- shooting paint balls and shouting chants against him and the opposition movement , the son said . Attackers targeted his father 's house repeatedly to stop him from participating in Friday 's events , said Mohammad Taghi Karrubi . The opposition leader 's website said his apartment had come under attack four times in four consecutive days . The site said the head of his security team was in a coma after being beaten as he tried to talk with a group of attackers who broke into the apartment complex Thursday . His son told CNN the attackers fired shots , set small fires in the courtyard and lobby and vandalized parts of the building . But around the country Friday , Quds Day demonstrations continued . Large crowds chanted `` Death to Israel '' and `` Death to America '' in Palestine Square near Tehran University . In the city of Kerman , a man with a loudspeaker chanted the slogans , with the crowd repeating after him . Some were carrying Iranian flags and banners supporting Palestinians while others waved cartoon caricatures of U.S. President Barack Obama . Speaking at Tehran University , Iranian President Mahmoud Ahmadinejad denounced Israel , repeatedly referring to the `` Zionist regime . '' He said this week 's direct Middle East peace talks in Washington were doomed to fail . `` These talks are dead . There is no reason to hold talks , '' he said . `` The fate of Palestine will be determined on the ground in Palestine , not in Washington and not in London , '' he added . Ahmadinejad said Iranians sympathize with Palestinians . `` We know how hard it is for them to resist , '' he said . As he spoke , the crowd chanted , `` Death to Israel . '' Security forces lined the streets near Haft-e-Tir Square in central Tehran , and at least two people were detained . There were no reports of opposition clashes . Last year , demonstrators took the streets in anti-government protests , shouting `` Death to the dictator '' in particularly tense rallies following the unrest over Iran 's disputed presidential elections in June . Clashes between security forces and protesters were reported around the university during Iranian President Mahmoud Ahmadinejad 's speech last year . On Thursday , Mohammad Taghi Karrubi told CNN that attackers had repeatedly come to his father 's house because he had expressed his desire to take part in Friday 's events . He said he was inside his father 's fifth-floor apartment when about 20 Basij broke into the courtyard Thursday . Several of the men threatened to kill his father , he said . `` When we asked the police to come to help ... nobody came , '' he said . Asked who was responsible , he said , `` They are in the name of the Basij , but in my opinion they are hooligans . The government tries to use these hooligans against the opposition and against the people . '' Several members of his father 's security team were injured -- but not shot -- and were taken to a hospital , he said . Asked if he and his father planned to attend Quds Day events on Friday , he said , `` Do you think we 'll still be alive tomorrow morning to take part ? '' International Quds Day , or `` Jerusalem day '' is observed on the last Friday of Ramadan . The government sponsored holiday was established in August 1979 by the late founder Ayatollah Ruhollah Khomeini shortly after the Islamic Revolution . Khomeini called for all Muslims worldwide to participate in the events that denounce Israel and show support for the Palestinian cause . `` The day for those nations suffering under the pressure of American oppression and oppression by other powers to confront the superpowers ; it is the day when the oppressed should arm themselves against the oppressors , '' he said in a speech in August of 1979 . Anti-Zionist demonstrations , parades , and seminars are held in some Muslim and Arab countries , but are especially large in Iran . A senior Iranian commander says the massive participation proves the global support for Palestinians . The Quds Day `` appears to pave the way for the collapse of Israel and its allies , namely the U.S. and Britain , '' Brig . Gen. Masoud Jazayeri , the deputy head of Iran 's armed forces joint chiefs of staff , told the Islamic Republic News Agency on Thursday .
NEW : Son says attackers targeted his father 's house repeatedly to stop him from participating . Comment: Ahmadinejad denounces Israel in a university speech . Some protesters are carrying Iranian flags and banners supporting Palestinians in the annual event .